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ISSN 0007-1 595 

Bulletin of the 

British Ornithologists' Club 

Centenary volume 


Edited by 

Volume 1 1 2a 

October 1 992 

TOS, 10%. 





A*J Idols' 

Bull. B.O.C. Centenary Suppl. 1 992, 1 1 2A 1 Ernst Mayr 


A jubilee is a time for congratulation and a time to look back as well as 
forward. Having attended my first dinner of the BOC 62 years ago, and 
having read the Bulletin even earlier than that, it gave me great pleasure to 
accept the invitation to say a few words as introduction to this centenary 

The BOC was founded in October 1892, to provide an opportunity 
to the members of the BOU "for meeting more frequently than the 
customary once a year". That there was a real need for the new organis- 
ation is documented by the fact that 84 members joined the Club in the 
first year and that all meetings were well attended. The early meetings 
were devoted almost exclusively to the showing of skins of new or rare 
birds or of plumage aberrations. The mood of the period is well-reflected 
by Bowdler Sharpe's singling out a special event in the history of the 
young club — "The exhibition of two unrecorded eggs of the Great Auk is 
sufficient to endow the proceedings of the Club for 1893-94 with more 
than ordinary interest." Indeed, the demonstration of eggs was a regular 
feature of the meetings. Most of the members had their own skin or egg 
collections and were intensely interested in new species and in having 
the opportunity to see rarities. Occasionally there were informative 
lectures such as one by Edward Degen on the evolution of the bird's wing, 
published as Volume 2 of the Bulletin. 

Forty years on, when I was able to attend some BOC dinners, they 
were yet memorable occasions. What a galaxy of stars attended them: 
Lord Rothschild, E. Hartert, W. L. Sclater, Ticehurst, Whistler, 
Meinertzhagen, Admiral Lynes, Stuart Baker, Gregory Mathews, 
Kinnear, Rev. Jourdain and many others. They all knew each other 
intimately and all enjoyed the festive spirit of the occasion. Of course, 
there was also some friendly bantering, and, among the egg collectors, 
there may have even been some who would not speak to each other. Rev. 
Jourdain was not at all amused when Col. Meinertzhagen sitting next to 
him handed him the box of cigars (with a few cigars left in it) saying, "And 
you take the whole clutch, as you are wont to do". 

Even more important than this cementing of friendship was the estab- 
lishing of the Bulletin by the Club. From the beginning it had a special 
niche in the ornithololgical literature, as a means for the rapid publication 
of ornithological novelties. In the first volume, 25 new genera were 
proposed and 54 new species were described. Sharpe, who was the editor 
of the Bulletin, was a strong believer in binomial nomenclature. "I cannot 
get three names on a label", he is said to have once said. As a result, in 
Volume 1 only one new bird was described as a subspecies, while 54 
others were named species. I analysed these names and found that 11 
were actually good new species, 28 are now considered subspecies and 
15 were synonyms. The novelties presented at the Club included such 
spectacular things as 2 new species of albatross and numerous examples of 
the marvellous discoveries of endemic Hawaiian species and genera. 

The spirit of ornithology has changed in the last 100 years, and the 
Bulletin has greatly enhanced its original usefulness. This is perhaps best 

Ernst Mayr 2 Bull. B.O.C. 1 1 2A 

documented by the fact that its membership has grown from 84 to some 
620 with more than 230 of them living overseas. Indeed, the Bulletin is a 
truly international publication. With the Ibis having more and more 
shifted to ecological, behavioural, physiological and evolutionary 
papers — the same being true for the major ornithological journals in the 
USA, Germany and other countries — there is a real need for a journal 
publishing short papers on questions of taxonomy at the subspecies and 
species level, on significant range extensions, on aspects of the history of 
taxonomy, and similar subjects. The Bulletin is filling this important 
niche quite admirably. 

It is rarely mentioned these days that Darwin's findings and conclu- 
sions in the Origin of Species were largely based on taxonomic studies. It is 
usually also ignored that the major contributions to the evolutionary 
synthesis in the 1 930s-40s, made by Th. Dobzhansky, G. G. Simpson, E. 
Mayr and B. Rensch, was largely the result of taxonomic reasearch. Nor 
is it realized by those of our contemporaries who work strictly on the 
gene-molecular level that their own findings are quite meaningless unless 
placed onto the framework of good systematics. For these reasons I am 
firmly convinced that even today taxonomy is not a backwater, but an 
important branch of biological science. Whenever we do comparative 
researches in biology, a comparison makes sense only when based on a 
sound classification. 

The new sphere of interest of the Bulletin is excellently reflected in this 
centenary issue, which deals with an admirable diversity of subjects. The 
emphasis has remained on taxonomy, but it reflects a new systematics in 
being, a far cry from the typological approach of the founders. Special 
attention is now paid to the ecological and behavioural interactions of 
species, to the analysis of the status of isolated populations, to the 
consideration of bioacoustics, and even to a survey of the new molecular 
methods which have already contributed so much to our understanding of 
the relationship of avian species, genera and families. There is no 
doubt the contents of the Bulletin are right at the frontier of modern 
ornithological research. 

The youthful vigour displayed by the Bulletin guarantees many more 
years, may I say centuries, of useful contributions to the advance of 
ornithological science. My best wishes and warmest congratulations. 

June 1 992 ERNST MAYR 

Museum of Comparative Zoology, 

Harvard University, 


Massachusetts, U.S.A. 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 3 W.J. Bock, SCON Chairman 

Status and future activities of the Standing 

Committee on Ornithological Nomenclature 

of the International Ornithological 

Committee (IOC) 

by Walter J. Bock 1 

Received 9 August 1991 



Central to the work of all ornithologists is a set of universal and stable 
names for the organisms they study. This problem is well known and 
appreciated by those committees 2 currently developing lists of vernacular 
names for birds, be these names, English, German, French or Spanish. 
Biologists have long recognized the importance of a universal, stable set of 
scientific names for organisms and in the early years of the 19th century 
had begun development of procedures and codes regulating the accep- 
tance and use of these names. This was not an easy task and several 
different sets of rules, such as the Strickland and the American Ornithol- 
ogists' Union Codes, gradually developed and were used by diverse 
groups of zoologists during the 19th century. Important procedural 
changes occurred during this period, such as the date to accept for the 
start of zoological nomenclature, different workers accepting differing 
starting dates. Some workers accepted pre-Linnaean names, and others 
used the 1st edition of Linneaus as the beginning of zoological nomen- 
clature. Most workers during the first half of the 19th century accepted 
the 12th edition of Linnaeus (1766) as the beginning of zoological 
nomenclature, but gradually during the second half of the 1800s, the 
10th edition of Linnaeus (1758) became widely accepted, and by the end 
of the century was used by almost all zoologists as the onset of zoological 
nomenclature. These diverse concepts and practices of nomenclature, 
involving rules of priority, led to major instability and lack of universality 
in scientific names for animals. Indeed many of the most muddled 
nomenclature problems in birds resulted from these different nomen- 
clatural procedures, not from the discovery of previously unknown 
names. In 1890, the International Congress of Zoology, the only truly 
international group representing all zoologists, established an Inter- 
national Commission on Zoological Nomenclature (ICZN) and charged 
this body with formulating a code of nomenclature acceptable to all 

'Chairman, SCON; Member, International Commission on Zoological Nomenclature; 
Secretary, International Ornithological Committee. 

2 At the International Ornithological Congress in New Zealand at Christchurch in 1990, the 
IOC established 2 standing committees to work on world lists of vernacular names of birds. 
One committee under the chair of Burt Monroe, Jr. will work on a list of English names for 
birds and the other under the chair of Henri Ouellet will work on French names. Any group 
of international ornithologists interested in establishing a similar subcommittee to work on 
world lists of names of birds in other languages should contact the author. 


W. J. Bock, SCON Chairman 4 Bull. B.O.C. 1 12A 

zoologists; but not until 1902 was a unified code of zoological nomen- 
clature adopted by the International Congress of Zoology (ICZN 1902). 
It was edited and published as "Regies Internationales de la Nomenclature 
Zoologique" in 1905 (Blanchard 1905). These Regies were amended many 
times up to 1930, but not thereafter, and had become seriously out-of- 
date by the time of the 1948 Paris zoological congress. Hence, the ICZN 
decided that a complete revision of the Regies was needed. A full 20 years 
were devoted to this revision which was finally adopted by the 15th 
International Congress of Zoology, London, 1958 and, after extensive 
editing, was published as the 'International Code of Zoological 
Nomenclature" (ICZN 1961), which exists today in the 3rd edition 
(ICZN 1985) and is generally called by zoologists interested in zoological 
nomenclature the 'Code'. 

Although these codes have served admirably to regulate the acceptance 
and use of scientific names, many problems both general and particular 
still exist. Among these is the fact that ornithologists need to know several 
names for most species, genera and families of birds if they are searching 
the literature for information on a particular taxon. For example, if one is 
interested in finding information on the Barn Owl Tyto alba in the 19th 
century literature, one must remember to look under the name Strix, by 
which this bird was known for most of the 1800s as well as Hybris and 
Aluco. The family-group name Strigidae was applied to all owls or, if 
subgroups were recognized, to the barn owls for most of the last century. 
The generic name Procellaria and the family-group name Procellariidae 
was applied to either the storm-petrels or to the shearwaters for much 
of the 19th century, depending who was the author. The generic name 
Colymbus Linneaus, 1758 and the family-group name Colymbidae rep- 
resented an especially recalcitrant nomenclatural problem. European 
workers applied these names to the divers or loons, while North American 
ornithologists used them for the grebes, the difference in use depending 
on interpretation of unclear taxonomic and nomenclatural decisions 
made by Brisson in 1760. This problem was analysed in great detail by 
Salomonsen (1951) at the 1948 International Ornithological Congress, 
Helsinki, 1948, his paper leading to an application to the ICZN for a 
plenary decision. This resulted in Colymbus being suppressed and the 
names Gavia for the divers and Podiceps for the grebes being conserved 
along with the associated family-group names. But more importantly, 
Salomonsen's presentation to the 10th ornithological congress resulted 
in the formation of the Standing Committee on Ornithological 
Nomenclature (SCON). 

Standing Committee on Ornithological Nomenclature 

The first SCON was elected by members of the 10th International 
Ornithological Congress attending a special meeting arranged after the 
presentation of Professor Salomonsen's paper (Proc. Xth Internat. 
Ornith. Cong. 154). The original members were J. Berlioz (France), R. 
Meinertzhagen (UK), E. Stresemann (Germany) and J. Zimmer (USA) 
under the chairmanship of Richard Meinertzhagen. The first detailed 
report of this committee was presented by Salomonsen at the 12th 

Bull.B.O.C.WlA 5 Status of SCON, IOC 

congress (Salomonsen 1960); but the committee had been most active 
from its earliest beginnings. 

The SCON functions under the authority of the International 
Ornithological Committee (IOC), the international body of ornithol- 
ogists responsible for the International Ornithological Congresses. As 
with other standing committees acting under the IOC, the members of 
the SCON from the first have been appointed every 4 years shortly after 
the close of an ornithological congress by the new president. Appoint- 
ments are made on the basis of the recommendation of the chairman of the 
previous SCON, which is formulated by discussion among the members 
of the committee. Dr. Eugene Eisenmann (American Museum of Natural 
History) served on this committee for many years including as its 
chairman, a position he held at the time of his death in October 1981. 
When informed in December 1981 of Dr. Eisenmann's death, Professor 
L. von Haartman, President of the 18th ornithological congress, 
appointed W. J. B. to this committee and asked if he would serve as its 
chairman. He has served in that capacity until the present time. Currently 
the SCON is composed of 14 members, as follows: Walter J. Bock, 
Chairman (USA), Murray D. Bruce (Australia), David Holyoak (UK), 
Ernst Mayr (USA), Gerlof F. Mees (The Netherlands), Burt Monroe, Jr. 
(USA), Hiroyuki Morioka (Japan), Henri Ouellet (Canada), D. Stefan 
Peters (Germany), Richard Schodde (Australia), L. S. Stepanyan 
(USSR), Karel H. Voous (The Netherlands), David Wells (Federation of 
Malaysia), and Hans E. Wolters (Germany) [fDecember 1991], 

The SCON serves as an advisory body on matters of avian nomen- 
clature. In this capacity, it holds open meetings at ornithological 
congresses to discuss current nomenclatural problems including pending 
applications before ICZN, to reach decisions on these matters and to 
chart its actions for the next 4 years. These meetings are open to all 
members of the congress, who are encouraged to take full part in the 
deliberations. Between congresses, the SCON remains active, dealing 
with nomenclatural problems as they develop and, when necessary, 
writing applications for submission to the ICZN and comments on 
pending applications. 

The SCON also serves as an information source for avian biologists on 
all matters of ornithological nomenclature, including interpretation of the 
Code, assisting in the analysis of particular nomenclatural problems and 
helping in the writing of applications to the ICZN. The SCON is most 
anxious to interact with individual ornithologists and with national check- 
list committees, and would appreciate being informed of all nomenclatural 
problems being considered by individuals and national committees. Unfortu- 
nately this interaction is at a far lower level than the SCON would prefer. 
All ornithologists and all national check-list committees are urged to 
inform the SCON, either the Chairman directly or any member, of all 
questions on ornithological nomenclature being discussed. Greater 
interaction between the SCON and the ornithologists would result in 
better nomenclatural decisions and more stable scientific names for birds. 

Through the Specialist Subcommittee on Ornithological Nomen- 
clature the SCON also serves as an advisory body to the ICZN on matters 
of avian nomenclature. It reviews all applications published in the 

W. J. Bock, SCON Chairman 6 Bull. B.O.C. 1 12A 

Bulletin of Zoological Nomenclature and submits its recommendations 
and opinions to the ICZN. Although the SCON has pressed for a greater 
role as a Specialist Subcommittee since 1982 and although the ICZN is 
strongly in favour of the development of these specialist advisory groups, 
the Secretariat of the ICZN has shown considerable reluctance to use 
such specialist advisory groups. However, the SCON believes strongly 
the Specialist Subcommittees are in a better position than the ICZN 
to deal with nomenclatural matters restricted to particular groups of 
animals. The SCON will continue to develop its role as a Specialist 
Subcommittee under the ICZN. 

The Secretariat of the ICZN (c/o International Commission 
Zoological Nomenclature, The Natural History Museum, Cromwell 
Road, London, SW7 5BD, U.K.; Dr. Philip K.Tubbs, Executive 
Secretary and Editor, Bulletin of Zoological Nomenclature) serves as the 
administrative body of the Commission. All inquiries about the work of 
the Commission, applications to the ICZN, questions about nomen- 
clatural problems, orders for publications of the Commission should be 
addressed to the Secretariat. Inquiries about ornithological nomenclature 
can also be addressed directly to the SCON. The Secretariat, ICZN 
publish quarterly the Bulletin of Zoological Nomenclature , now in its 48th 
volume. All applications to the ICZN, comments on these applications, 
decisions by the ICZN and discussions about zoological nomenclature 
appear in their Bulletin. In addition, the International Code of Zoological 
Nomenclature (1985, 3rd edition; £19.00 or $35.00), the Official Lists 
and Indexes of Names and Works in Zoology (1987; £60.00 or %\ 10.00) 
and its supplements may be ordered from the Secretariat. 

Family-group names 

With the publication of the new Code, family-group names were sub- 
jected to considerably greater regulation, including extending priority to 
these names. Unfortunately the new Code did not contain a clear stare 
decisis ( = "grandfather") clause, and many workers chose to overlook its 
finer details. The changes to the rules of nomenclature were made with 
little analysis of their effect on existing and often well-established family- 
group names, but, and it must be emphasized, these changes in the new 
Code (ICZN 1961) affecting family-group names are far more complex 
than the simple extension of priority to these names. The Code is quite 
clear that the application of priority to family-group names was not to be 
used to upset established names, and it should be noted that it clearly 
states that names for taxa above the family-level are not covered by the 
rules of zoological nomenclature. With high probability, the Code will 
not be extended to names for these higher level taxa. 

Beginning with the 1962 congress in Ithaca, NY, the SCON expressed 
its concern on the effects of the extension of priority in the new rules on 
many well-established family-group names of birds which did not possess 
priority. Several unsuccessful attempts were made to declare a list of well- 
established family-group names for the Oscines (see Salomonsen 1960: 
38-39), but such broad-based applications were never accepted by the 
Secretariat of the ICZN. A few individual family-group names, such as 

Bull.B.O.CAUA 7 Status of SCON, IOC 

Thraupinae, Cardinalinae and Drepanididae, were conserved. However, 
nothing further was done for 20 years because of the daunting prospects 
of searching out all the avian family-group names in the old literature. 

At the meeting of the SCON during the 1982 ornithological congress, 
Moscow, the decision was reached that the SCON would take proper 
action to resolve the problem of avian family-group names (Bock 1985). I 
undertook the task to research the history of these names and to prepare a 
list of family-group names published for avian families using the standard 
classification in Peters' Check-list of Birds of the World. A draft of this list 
of names was presented at the 1986 congress, Ottawa, where the SCON 
voted to complete this project and to publish the list of avian family-group 
names of Recent birds (Bock 1989). A final draft (Bock, in prep) was 
circulated to members of the SCON and other interested ornithologists 
just prior to the 1990 congress, Christchurch, and this list and future 
action by the SCON were discussed at the open meeting there. Copies of 
this final draft are available to interested ornithologists by writing to me. 
Over 1200 family-group names are available for Recent birds (i.e. those 
covered in Peters' Check-list); the list does not include names for families 
of fossil birds. After this list is published, an application will be made 
to the ICZN, requesting that this list of avian family-group names be 
declared as the base-line for all future nomenclatural decisions of avian 
family-group names for Recent birds. The names on this list, with their 
authors and dates of publication, by such declaration will be fixed; and 
names not on this list will be declared not available for purposes of 
zoological nomenclature for Recent birds. These actions are in line with 
the current thinking of the ICZN, which is to encourage the development 
of lists of available names for groups of animals, and to fix these lists as the 
only names available for each group. 

Generic names 

Following discussion of the list of family-group names, the SCON 
considered the general concept advocated by the ICZN to develop lists 
of available names for groups of animals. The group approved of this 
approach and proposed a resolution for consideration by the IOC at 
its meeting. This resolution which was approved by the IOC reads as 

'WHEREAS the International Commission on Zoological Nomenclature has the difficult 
central role in insuring maximum ease of communication between zoologists by insuring the 
stability and universality of names for the diverse organisms studied by the zoologists, 
THEREFORE BE IT RESOLVED that the International Ornithological Committee at its 
meetings during the XX International Ornithological Congress, Christchurch, New 
Zealand, 2-9 December 1990 congratulates and supports the International Commission on 
Zoological Nomenclature in its efforts to increase continuity of zoological nomenclature by 
the conservation and stabilization of established names and directs its Standing Committee 
on Ornithological Nomenclature to assist the International Commission on Zoological 
Nomenclature in these efforts. 

MOREOVER, the International Ornithological Committee recognizes and congratulates 
the pioneering actions of the Standing Committee on Ornithological Nomenclature in 
developing a list of available family-group names of birds and urges this committee to 
undertake similar projects on genus-group and species-group names of birds.' 

W.J. Bock, SCON Chairman 8 Bull. B.O.C.W2A 

In connection with this resolution, Murray Bruce said that he was 
developing a computer-based data bank of generic names for birds. The 
SCON discussed the possibility of undertaking a project of completing 
this list of available generic names for birds similar to that completed for 
family-group names, publishing it and applying to the ICZN to declare 
this list as the base-line for all future nomenclatural decisions on generic 
names for Recent birds. This project was approved and Murray Bruce 
and Walter Bock were directed to consider ways to complete the project 
after the list of family-groups names was finished. 

Delays in actions taken by the ICZN 

Many members of the SCON and other ornithologists have expressed 
serious concern about the long waits on applications submitted to the 
ICZN, delays arising in the work of the Secretariat. For example, the 
application on conserving the family-group name Threskiornithidae was 
submitted in 1975 and published only in 1984; but to date it has not been 
submitted to the membership of ICZN for their vote. The application to 
conserve the generic name Cacatua was published in 1964, with a substi- 
tute set of requests published in 1965. Although ornithologists have 
agreed informally to use this name, the Secretariat of the ICZN delayed a 
vote for apparently rather trivial reasons. After a full discussion of these 
and other cases, the SCON voted to urge the ICZN and its Secretariat to 
speed the measures by which applications are processed, published and 
final action taken by the ICZN. Further, the SCON urged the ICZN and 
its Secretariat to increase its use of the SCON as a specialist advisory 
committee and to submit to the SCON for its consideration all appli- 
cations, upon receipt, dealing with birds. At the same time, ornithologists 
are strongly urged to interact with the SCON in their analysis of possible 
nomenclatural matters and in the development of applications for 
submission to the ICZN. 

Because ornithologists rarely contact the SCON on nomenclatural 
analyses they have undertaken, and usually do not inform the SCON of 
their individual applications and comments submitted to the ICZN, the 
SCON does not and cannot have a good appreciation of the magnitude of 
this problem of delays. For example, we do not know of, or how many, 
applications on avian nomenclatural matters have been submitted to the 
ICZN and are still unpublished. Therefore, all ornithologists are urged to 
keep the SCON informed of their correspondence with the ICZN, 
including where possible sending copies of all applications and comments 
and of all correspondence with the Secretariat. The SCON would appre- 
ciate learning of any problems, including delays in publications, extensive 
editing of applications and comments in which real changes of meaning 

Scientific names used for birds affect the work of all ornithologists, and 
the SCON is dedicated to the central goal of the International Code of 
Zoological Nomenclature, as expressed clearly in its Preamble, namely 
the maximum stability and universality of these names. This goal can best 
be reached by full cooperation between all ornithologists. The SCON 
appreciates the offer of the British Ornithologists' Club to present this 

Bull.B.O.C. 112A 9 Status of SCON, IOC 

report of its recent activities and we hope that its publication will 
encourage ornithologists worldwide to interact more with the Standing 
Committee on Ornithological Nomenclature and its work. 


Blanchard, R. (Ed.). 1905. Regies Internationales de la Nomenclature Zoologique Adoptees por 

la Congres Internationaux de Zoologie. F. R. Rudeval, Paris. 
Bock, W. J. 1985. Report of the Standing Committee on Ornithological Nomenclature. 

Proc. XVIIIth Internat. Ornith. Cong., Moscow, 1982: 29-32. 

— 1989. Report of the Standing Committee on Ornithological Nomenclature. Proc. XlXth 

Internat. Ornith. Cong., Ottawa, 1986: 62-68. 

— 1992. Report to the XXth International Ornithological Congress from the Standing 

Committee on Ornithological Nomenclature. Proc. XXth Internat. Ornith. Cong., 
Christchurch, 1990: 84-86. 

— In Prep. History and nomenclature of avian family-group names. 

International Commission on Zoological Nomenclature (ICZN). 1902 Rules of Zoological 
Nomenclature. [English Version of the "Regies internationales de la Nomenclature 
zoologique."]. Pp. 963-972. In: 'Verhandlungen des V Internationalen Zoologen 
Congress zur Berlin. 12-16 August 1901'. P. Matschie, Ed. G. Fischer, Jena. 

— 1961. International Code of Zoological Nomenclature, adopted by the XV International 

Congress of Zoology. Internat. Trust Zool. Nom., London: xviii + 176 pp. 

— 1985. International Code of Zoological Nomenclature, adopted by the XX General 

Assembly of the International Union of Biological Sciences. Third Edition. Internat. 
Trust Zool. Nom., in association with the British Museum of Natural History, London 
and the University of California Press, Berkeley and Los Angeles: xx + 338 pp. 
Salomonsen, F. 1951. A nomenclatural controversy: The genus Colymbus Linnaeus 1758. 
Proc. Xth Internat. Ornith. Cong., Uppsala: 149-154. 

— 1960. Report of the Standing Committee on Ornithological Nomenclature. Proc. Xllth 

Internat. Ornith. Cong., Helsinki: pp. 30-43. 

Address: Dr. Walter J. Bock, Dept. of Biological Sciences, Columbia University, New 
York, NY 10027, USA 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 1 1 D. Amadon & L. L. Short 

Taxonomy of lower categories — suggested 

by Dean Amadon & Lester L. Short 

Received 7 January 1992 


In the 1940s came a wider realization that evolution provides the theme 
for all aspects of biology. One of the pillars of this synthesis was a ''bio- 
logical" species concept, sponsored then and later by Mayr (1942, 1963), 
among others. Reduced to essentials, a species is a self-contained, inter- 
breeding, interfertile population. Each such reproductively isolated 
species is forever on its own — to evolve, to adapt, or to face extinction. Such 
species, and the individuals comprising them, constitute the diversity and 
richness of life on earth. Recently this species concept has come under 
scrutiny and some opposition. On the one hand the virtual explosion of 
new laboratory techniques, here subsumed under the rubric "molecular 
biology", has permitted penetrating analyses of populations. In another 
direction, more rigorous cladistic methods of phylogenetic analysis, 
associated in part with the work of Hennig (1966), pose new questions. 

Several other species concepts have been proposed in recent years. 
Meanwhile the scientific community and the public at large continue to 
rely on the prevailing understanding of this taxon. The biochemist seek- 
ing a vaccination for malaria assumes that he has been correctly informed 
by the taxonomist that the mosquitoes before him are the vector of a 
particular strain of malaria. The conservationist assumes that the species 
he is seeking to preserve are realities. 

We briefly review some conflicting species concepts and conclude that, 
while they shed new information on the complex and variable evolution- 
ary process of speciation, they pose no threat to the belief, may one call it a 
fact, that the vast majority of living organisms are (or for fossils, were) 
organized into the self-contained interbreeding units, which Noah, load- 
ing his Ark, called species. Our main purpose is to present an ordered 
scheme of categories dealing with taxa at or near the species level. As we 
make clear below, one is obliged in consideration of taxa at any given level, 
to treat matters to the next higher level (here, the genus) and to the next 
lower level(s), subspecies and even demes. Others have initiated this pro- 
cess, piecemeal, as indeed have we (see References). A few new terms are 
defined as necessary to complete the framework. 

The working taxonomist is faced with various problems. New termin- 
ology is rife; we attempt to separate what is useful from what is superfluous 
or impractical. Taking it for granted that since the time of Darwin classi- 
fications should embody as much as possible of known or presumed 
phylogeny, to what extent can the veritable flood of information and theory 
from molecular biology and cladistics be incorporated into a classification, 
and what part left to cladograms or other means of presentation? Must not a 
classification also reflect degree of change; after all to evolve is to change 

D.Amadon&L.L. Short 12 Bull. B.O.C. 11 2A 

over time. If on some planet the only result of 3 or 4 billions of years of 
evolution were 200 or 300 nearly identical species of "seaweeds", how 
significant would a cladistic analysis of their phylogenies be? Linnaeus, a 
century before Darwin, set up his higher categories because he realized 
that, for example, seals are less closely related to cats than is one genus of cat 
to another. Several of the definitions refer to monophyly. Some groups 
have so many traits in common, that monophyly can scarcely be ques- 
tioned; e.g. the living species of flamingoes (Phoenicopteridae). Often 
however, especially when based on fossil specimens, few and imperfect, 
monophyly is a tentative conclusion. The methods and special taxonomy 
of cladistics are of assistance, though fossils pose major problems (Van 
Valen 1978). Molecular biology plays an increasing role but with rare 
exceptions is limited to living or recently extinct organisms. 

Definitions of terms 

To facilitate discussion we begin by defining the terms that we find 
essential or useful. The numbers correspond to those in the following 
analysis. Three terms, marked with an asterisk, are here introduced for 
the first time. Four of the terms: species, subspecies, genus, subgenus are 
formal designations, rules for whose usage are set forth in the Rules of the 
International Commissions on Nomenclature — botanical and zoological. 

1— SYMPATRIC (SYMPATRY). Taxa that occur in the same area (range) at least in 
part and at least during the reproductive season. 

2— ALLOPATRIC (ALLOPATRY). Taxa whose ranges do not overlap, at least 
during the reproductive season. 

a— PARAPATRIC ALLOPATRY. Allopatric taxa whose ranges are (in part) 
contiguous, but do not overlap. 

b — DISJUNCT ALLOPATRY. Allopatric taxa whose ranges are spatially separated. 
3 — DEME. Within a species, a localized diagnosable subpopulation of less than 
subspecies rank. 

4- — SUBSPECIES. Within a species, a named, recognized allopatric subpopulation 
which is (still) genetically compatible with other subpopulations, but is set apart by a 
concordant array of genetic and phenotypic characters. 

5 — MESOSUBSPECIES*. A subspecies that is not approaching species status. 
6 — MEGASUBSPECIES. A subspecies that is approaching species status. 
7 — SUBSPECIES GROUP. A monophyletic subset of subspecies within a species. 
8— (SEXUAL OR GAMETIC) SPECIES. A freely interbreeding, interfertile, self- 
contained population (or group of subpopulations) of organisms. 

9 — MONOTYPIC SPECIES. A species without recognized subspecies. 
10— POLYTYPIC SPECIES. A species with recognized subspecies. 
11 — MESOSPECIES*. A polytypic species none of whose subspecies is approaching 
species status. 

12 — MEGASPECIES. A polytypic species composed of megasubspecies. (Term 
introduced by Crawford-Cabral 1986.) 

1 3 — ISOSPECIES*. A species that is not a member of a contemporary superspecies, i.e., 
that is not an allospecies. 

14 — ALLOSPECIES. One of the allopatric species comprising a superspecies. 
15 — SIBLING SPECIES. Species so similar phenotypically that they are hard to 

16 — GENUS. A named, recognized, monophyletic group of species, in rank between the 
species and the family (or subfamily). 

17 — SUBGENUS. A named, recognized, monophyletic subset of species within a genus. 

18 — POLYTYPIC GENUS. A genus containing more than one species. 

19— MONOTYPIC GENUS. A genus containing only one species. 

20— QUASI-MONOTYPIC GENUS. A genus consisting of one superspecies. 

Bull. B.O.C. 1 1 2A 13 Taxonomy of lower categories 

21 — SPECIES GROUP. A monophyletic subset of species within a genus or a subgenus, 
but not formally named (as are the genus and subgenus). 

22 — SUPERSPECIES. A group of allopatric species (hence allospecies) deemed to have 
been derived from (mega)subspecies of a single antecedent species. 

term applied to ISOSPECIES and to SUPERSPECIES considered as equivalents; that is, 
the allospecies of a superspecies are not listed or evaluated separately. 

24— ASEXUAL POPULATION, CLONE, or "SPECIES". A population in which no 
interchange of genes occurs among individuals. 

Discussion of terms 


From the definitions it will be evident that we consider parapatric 
allopatry and disjunct allopatry as two kinds of allopatry. Thus we do not 
follow Prigogine (1984, 1985) who recommended parapatry as a third 
category equivalent to sympatry and allopatry, limiting the latter to dis- 
junct allopatry. Some subspecies of a species may be parapatric, as on a 
continent, with others disjunctly distributed on surrounding islands. The 
same is true of the allospecies of a superspecies. Furthermore, as a result 
of changes in sea level, orogeny, or climate, taxa which were once para- 
patric may become disjunct or vice versa. Such changes may at times 
occur abruptly, due for example to stream capture, volcanic eruptions, or 
the like. The degree of geographic separation may vary from slight 
(patchy distribution) to great (on different continents). It seems best to 
subsume parapatric allopatry and disjunct allopatry under allopatry. 

Parapatry infers visual and vocal contact, and thus the opportunity for 
physical contact between individuals of 2 taxa in the appropriate season or 
time of year for breeding activity (subspecies and allospecies of birds may 
come into sympatry seasonally, through migration, when they do not 
breed). Taxa are not parapatric when, for example, they involve forest 
animals separated by a broad river which they do not cross, and across 
which they cannot hear or see individuals (but at the headwaters of such a 
river they may become parapatric). 

The important fact is whether 2 taxa overlap and hence are ipso facto 
(sympatric) species or whether they are spatially separated and thus could 
be either subspecies or species. Taxa that are in parapatric allopatry are 
more profitably studied by the evolutionist than spatially separated ones 
because actual contact provides a test for the completion of speciation. 
Nevertheless, disjunct populations are a far more fertile source of new 
species, because of their often greater genetic isolation, and their frequent 
occurrence in more distinct ecotypes. 

Smith (1965) proposed the term "dichopatric" for what we have called 
disjunct allopatry; the term disjunct had been used for this purpose at 
times. Mayr (1982a, b) proposed a term "peripatric" for instances of dis- 
junct allopatry resulting from dispersal, hence "peripatric speciation." 
This will usually involve a small number of individuals, and will result in 
the "founder effect" of Mayr (1948a; see also Carson 1989). Cracraft 
(1984) agreed with this and went on to suggest that Smith's term dicho- 
patric be restricted to the other class of disjunct populations, those 
resulting from vicariant events such as orogeny. He noted that in some 
biogeographic and other analyses, it is useful to make this distinction. 

D. Amadon & L. L. Short 14 Bull. B.O.C. 1 12A 

Still, the terminology leaves something to be desired because dichopatric 
was originally proposed to apply to all types of disjunct allopatry, while 
peripatric is doubly confusing both because of its similarity to parapatric 
(when spoken as well as in print) and because such peripatric populations 
are not parapatric but disjunct. That is, it is not a kind of parapatry. 
Probably in those instances where it is necessary to make the distinction, 
it may best be simply explained which type of disjunct allopatry is meant. 

3— DEME 

Species, except those with very small ranges, or perhaps wide-ranging 
promiscuous ones (some cetaceans), tend to become subdivided into allo- 
patric, local, often weakly characterised, subpopulations called demes. 
Local populations of birds that have developed song dialects are 
examples. Such trends may at first have little or no genetic basis, but if 
dispersal and gene flow are minimal and isolation continues, these demes 
can evolve through subspecies to species. Or, adaptive gene combinations 
may become established more easily in small populations like demes and 
can then gradually permeate the entire species. 


When subspecies are in parapatric allopatry they interbreed and 
exchange genes where their ranges meet. This will usually not lead to 
genetic swamping and the merger of the subspecies, for each is often 
adapted to a slightly different ecotype. Equally important, however, as 
with demes, favourable gene combinations may spread throughout the 
species. The amount and nature of the gene flow are affected by popu- 
lation structure, dispersal rates, the distribution of preferred habitats, 
and other factors. The access of diverse populations to beneficial genes 
and gene combinations is potentially of great value, and is possible 
because of reproductive compatibility. When variation is clinal, as is 
often the case, it is unwise to name subspecies unless the terminal popu- 
lations are strikingly unlike. The same is true of non-concordant clinal 
variation; e.g., size may increase northwards and paleness westwards. 
Such variation may, to a degree, result from non-genetic (in the 
immediate sense) responses to slowly changing ecotypes. Put otherwise, 
most populations that warrant subspecific status will represent a more or 
less integrated suite of characters, some adaptive, some neutral. 

The use of the term "recognised" in the sense of 'Visibly different" in 
our definition of the subspecies is deliberate. The formal naming of spatial 
subpopulations should be restricted to those that are morphologically 
(phenotypically, and proven or presumed genetically) separable at some 
reasonable level, e.g. 90%. This is as true now as it was a half-century ago 
when Bullough (1942) unwisely named the resident European Starlings 
Sturnus vulgaris of Great Britain a subspecies, britannicus , to separate 
them from the phenotypically inseparable, migrant Scandinavian 
Starlings, which overwinter in the British Isles. 

Clamour for the abolition of the subspecies as a formal category has 
come mostly from those unconcerned with the broad aspects of geo- 
graphic variation and speciation; for defence of the subspecies see, e.g. 
Smith & White (1956), Amadon & Short (1976). The usefulness of 
traditional and formally recognized subspecies was discussed in a series of 

Bull. B.O. C. 1 1 2A 15 Taxonomy of lower categories 

short papers by Mayr (1982d) and others. Palaeontologists might be 
expected to have little need for subspecies, but Simpson (1961: 176) 
recommended "successional" (temporal) subspecies when analyzing 
some fossil sequences. 

Many taxa known by intergradation or reasoned by inference to be 
conspecific are nonetheless so distinct that taxonomists, general biolo- 
gists, conservation and government agencies, and laymen seek a name for 
them. By providing a subspecies name this need is met; further, the 
unfortunate tendency to elevate such infraspecific taxa to the status of 
species is lessened. In better known groups most such taxa already have 
names available. 

The simple scanning of check-lists or other publications in which sub- 
species are listed can provide information and suggest lines of investi- 
gation for many studies of biogeography, biodiversity, ecology and 
evolution, including: comparison of genetic variability with phenotypic 
variability; analysing why some congeneric species show more variability 
than others; comparison of levels of differentiation associated with degree 
of geographic isolation; size of range (islands); and amount of variation in 
migratory versus non-migratory populations. Subspecies are increas- 
ingly recognized as important in environmental conservation and the 
maintenance of biological diversity. Government agencies can (and 
should) deal with named, definable subspecies, which provide a con- 
venient, logical and biologically significant level of categorization for 
maintaining biodiversity (O'Brien & Mayr 1991). Endangered status, 
usually given when a species is reduced to a level below 5000 individuals, 
ought, for purposes of preserving significant genetic diversity, to be 
applied also at the subspecies level. Certainly this would serve the long- 
term goal of preserving biodiversity, and indeed species. It also obviates 
the need felt and too often expressed by some conservationists, to inflate 
subspecies to the level of species solely to preserve them. 

To be sure, too much emphasis upon subspecies when shaping public 
policy can occasionally be a double-edged sword. Efforts to save the 
gravely endangered Florida population of the cougar or "panther", Felts 
concolor, have been questioned because apparently a few individuals from 
Central America, which may represent a slightly different subspecies 
were at one time released in Florida, thus "tainting" the local population. 
But surely the important point is to save the only remaining remnant of 
the species in the eastern United States. 

Subspecies are accepted by Avise & Ball (1990); to qualify as a sub- 
species they ask that a population exhibit concordant characters, prefer- 
ably demonstrated molecularly, but add that sometimes a concordance of 
phenotypic characters will have to suffice because it is too much to expect 
that all populations of organisms will be analysed genetically. 

For those who would argue against formal recognition of the sub- 
species, it may be noted that this in no way alters the conclusion that 
there is a fundamental difference between infraspecies populations (not 
genetically isolated) and species (genetically isolated). Indeed, even those 
who may avoid formally named subspecies, will have to use some method 
of categorizing and ranking geographically isolated, distinctive, but 
infraspecific populations. 

D. Amadon & L. L. Short 16 Bull. B.O.C. 11 2A 


A term here proposed for the great majority of subspecies, those that 
are not approaching species status. Mesosubspecies may be well-defined 
by one or more traits, some at a level of 100% separation from one 
another. Several mesosubspecies may form one megasubspecies of a 
megaspecies, presenting problems addressed by Amadon & Short (1976). 
A polytypic species comprised only of mesosubspecies (that is, lacking 
megasubspecies), is a mesospecies as defined above. Mesosubspecies may 
be clustered into subspecies groups, if that is desirable. 


In an earlier paper we (Amadon & Short 1 976) introduced this term and 
suggested procedures for the use of parentheses to indicate them. Thus 
Circus (cyaneus) hudsonius indicates that the North American form of the 
Northern Harrier is judged to be a subspecies of the Eurasian Circus 
cyaneus, but one which is approaching species status. The 2 are com- 
pletely isolated geographically. In more general works merely the species 
name, Circus cyaneus, would be used for both. 

There are a great many such taxa, hundreds in the Class Aves alone, 
whose status, whether species or megasubspecies, is in part a judgmental 
opinion. In the harrier example, the 2 megasubspecies are not greatly 
different, but the genus is one with some quite similar sympatric species, 
which suggests caution. On the other hand a third taxon, related to the 2 
just noted, cinereus of South America, is much more distinct and we think 
it is a valid species. Then cyaneus and cinereus are the two allospecies of a 
superspecies Circus {cyaneus]. Thus the megasubspecies provides a 
repository for, as the definition states, taxa that, on the available evidence, 
are concluded not to have crossed the species threshold, but to be 
approaching it. (See also number 12, megaspecies, below.) 


The subspecies of polytypic species often permit separation into 
groups with shared characteristics, frequently along geographical lines. 
The category is informal, so one may use it without assigning all the 
subspecies in a species to subspecies groups (though it is often heuristic to 
do so), while recognizing that a single subspecies may form its own group. 
In megaspecies the megasubspecies themselves essentially constitute 
subspecies groups and it will rarely be worthwhile to attempt further 

Because of "leapfrog" or mosaic evolution, disjunct subspecies 
occasionally are phenotypically more similar than parapatric ones. Or, for 
example, dark-coloured subspecies of larks or mice may occur wherever 
there is a sizeable outcropping of black lava. To associate such sub- 
species may result in groups that are not monophyletic, requiring careful 
taxonomic analyses. 


Characteristics. A species is an interbreeding, interfertile (i.e. 
Mendelian) population of organisms. We have added "self-contained" 
rather than "kept separate from other populations (species) by isolating 
mechanisms". Carson (1989) favours such a concise definition as 

Bull. B.O.C. 112A 17 Taxonomy of lower categories 

emphasizing the sine qua non of the species, a common gene pool, and 
notes that Dobzhansky (1950), the pioneer in applying genetics to the 
species concept, did the same. 

The species is often, even usually, defined as "a group of interbreeding 
populations". This is misleading. Many, perhaps most, species evolve 
from a small isolated population — the "founder effect" of Mayr (1982a) 
or the "punctuated equilibria" (in part) of Gould & Eldredge (1977) (see 
also Barton 1989). Some species, because they always have small ranges, 
remain essentially panmictic; others become so as they decline towards 

Most species do eventually break up into more or less spatially segre- 
gated subpopulations. But these subpopulations, from one point of view, 
disrupt the species away from panmixia; when sufficiently isolated and for 
sufficiently long periods, they will diverge through the stages of deme, 
mesosubspecies, megasubspecies, species, and even genus. To define the 
species as based upon or requiring interbreeding populations is quite 
simply an error, but subpopulations must be mentioned to make it clear 
that these usually arise and remain part of a species for indefinite periods. 

Species vary over space and time and this, together with their intrinsic 
variability, as enhanced by sexual reproduction, open the way for the 
evolution of new species. It is not surprising that the species definition 
sometimes has to be qualified to cover specific cases, of which the 3 
following are among the more significant. 

(a) — As already noted, species, especially widely distributed ones, tend 
to break up into subpopulations. These may be in either parapatric or 
disjunct allopatry; some of the latter may be only "potentially" capable of 
interbreeding with other subpopulations, e.g. rats, Rattus, stranded on an 
island. Others, of course, are permanently stranded, as by the sub- 
mergence of the Siberian- Alaskan Landbridge, yet such populations may 
remain conspecific for long periods. 

(b) — Closely allied species (allospecies), sometimes continue to inter- 
breed (hybridize) to a limited extent; an extent insufficient to undermine 
their genetic integrity (see later discussion). 

(c) — Over geological time, fossil lineages must be arbitrarily broken up 
by the taxonomist into species, genera and families, keeping them as 
equivalent as possible to ones based on contemporary taxa. As Simpson 
noted (1961: 165), any species, living or fossil, e.g. Homo sapiens, could in 
theory be traced back generation by generation to a one-celled ancestor; 
but to designate such an entire lineage as a single species is "not only 
useless but somehow wrong in principle. Certainly the lineage must be 
chopped into segments (species, genera, families) for the purpose of 
classification and this must be done arbitrarily". Gaps in the fossil 
record, doubts as to exact lineage, and other factors make the process of 
subdividing such lineages less difficult than might be expected. 

Bock (1 986: 38) disagrees and concludes that species have no beginning 
and no end (except extinction). But if a species occurs in a Palaeocene 
fossil bed, for example, and a taxon in the same lineage in another deposit 
from the Eocene 1 5 million years later, but by now much changed, is there 
any recourse but to name it as new? To continue to use the name applied 
to a quite different earlier stage would be completely confusing. 

D. Amadon & L. L. Short 18 Bull. B.O.C. 1 12A 

Some cladists have tried to circumvent the problem of lineages over 
secular times by positing that every time a species buds off a new one, the 
parent species, too, becomes a "new" species. Nonetheless, assume that 
seeds of an African tree, for example, were blown to St. Helena Island, 
where they were picked up and planted by Napoleon in 1817 or 1818. If 
and when they diverge to the species level are we to suppose that the 
African tree, which continues on virtually unchanged, is to be designated 
a new species also? At what point in time is this to be done? Some trees in 
China and the Appalachians are so similar after many millions of years of 
separation that they may still represent only subspecies. 

Related species are kept from interbreeding by so-called (reproductive) 
isolating mechanisms. These are of 2 chief kinds: pre-zygotic (pre- 
mating) and post-zygotic (post-mating). Pre-zygotic barriers include 
vocalizations, odours (pheromones), 'courtship' displays (birds, fruit 
flies), and even patterns of light flashes (fireflies, Lampyridae). Such 
mechanisms seem insubstantial and indeed may begin as non-genetic 
variations, e.g. song dialects among birds. If isolation continues and is 
sufficient, they will acquire genetic bases; in the same period of time other 
distinctions will arise and, if secondary contact between 2 such groups 
occurs, may act as supplementary isolating mechanisms. 

Post-zygotic isolating mechanisms run the gamut from complete 
sterility, through sterile hybrids (e.g. mules), to more or less fertile 
hybrids which, however, may possess subtle disadvantages in nature. In 
all such cases natural selection will tend to reduce costly mis-matings, 
which leave no long-term, viable offspring and which may even result in 
hardy 'mules' that compete with both parent species. An exceptional case 
is provided by certain flightless, very sedentary, Morabine grasshoppers 
in Australia, populations of which are prone to acquire chromosomal 
alterations. When such populations meet parapatrically, they interbreed 
freely; there has not been time for pre-mating barriers to evolve (White 
1978, Key 1968). If 2 such subpopulations prove intersterile, speciation 
has occurred (called 'stasipatric' speciation); if some genetic interchange 
is possible, they are megasubspecies. 

The opposite occurs more commonly. Isolated populations gradually 
acquire differences that will later serve as pre-zygotic isolating mech- 
anisms (in voice, odour, behaviour, etc.) before genetic changes are 
sufficient to ensure sterility (post-zygotic separation). When such 
populations come into secondary contact, cross-breeding will be rare; but 
when it does occur, more or less fertile hybrids may result. 

A few instances are known in which normally reproductively isolated 
taxa, though not intersterile, for example on isolated mountains or on 
islands, have produced hybrid swarms (Short 1969: 96-97). This suggests 
that the hybrids may be superior under the insular conditions, that pre- 
zygotic isolating mechanisms are incompletely developed (or break 
down), and that post-zygotic isolating mechanisms are lacking. 

Two Mexican finches, Pipilo erythrophthalmus and ocai, interbreed in 
most areas where they meet, but are sympatric without interbreeding 
in one area (Sibley 1954, Sibley & Sibley 1969). In a few other cases 
supposed species (allospecies) are being hybridized out of existence: 
hybrids and one of the parental species apparently are being selected for 

Bull. B.O.C. 112A 19 Taxonomy of lower categories 

at the expense of the second species, e.g. the new Zealand Black Stilt 
Himantopus novaezealandiae, is being displaced by the Common Stilt 
H. himantopus leucocephalus (Pierce 1984) and the Black-eared Miner 
Manorina melanotis by the Yellow-throated Miner M. flavigula in 
Australia (R. Schodde and L. L. Short pers. obs.). In both cases there has 
been extensive modification of the environment by humans. It can logi- 
cally be argued that in such cases the taxa are megasubspecies and not 
allospecies, because otherwise the presence of effective isolating mechan- 
isms should make massive hybridization impossible between species. 
Extinction by hybridization should not occur in allospecies; if extinction 
does occur after secondary contract, it is because one of the allospecies 
proves to be selectively superior to the other and replaces (total extinction) 
or displaces (partial extinction) it through competitive exclusion. 

There may be rare exceptions, e.g. an allospecies restricted to an island 
subject to extensive human modification, followed by secondary entry by 
an allospecies, could result in hybridization and breakdown. It is even 
possible that a hybrid swarm could be the end product of the evolution of 2 
allospecies if all populations of those allospecies became extinct other than 
the hybrid swarm itself. It is significant that polyploid species of plants, or 
more rarely parthenogenic species of animals (lizards), survive, when 
they do, in ecotypes which have been much disturbed (usually by man). 

Competing Species Concepts. As noted, a continuing flurry of publi- 
cations on the species question has promulgated several different species 
concepts or definitions (Andersson 1990). While our approach is practical 
rather than theoretical, the species is so central to taxonomy and classifi- 
cation that it is desirable to discuss briefly some of these proposals as they 
relate to our proposed terminology. Aside from other publications cited 
herein, one may inter alia mention important ones by Chandler & 
Gromko (1989), Coyne et al. (1988) and Hauser (1987). 

(a) Evolutionary species. Simpson (1961: 153), primarily a palaeontolo- 
gist, proposed the following definition: "An evolutionary species is a 
lineage (an ancestor-descendant sequence of populations) evolving separ- 
ately from others and with its own unitary evolutionary role and tenden- 
cies." The word lineage implies an interbreeding population, viewed over 
time. Thus the definition again comes down to genetically isolated popu- 
lations. Indeed, Simpson stated that in an earlier published version of this 
definition he had included the word "interbreeding" but dropped it to 
include clones and asexual "species" (but see below). 

With the inclusion of the element of interbreeding, the evolutionary 
species definition becomes equivalent to the biological one. It does 
emphasize the temporal element: that species (and life) are a succession of 
individuals and populations. Indeed, only these 2 definitions are readily 
applicable to fossil as well as extant taxa. It further emphasizes that 
species have roles and tendencies, and as noted below that they have 
individual ecological niches. This need not be appended to the definition. 

(b) 'Ecological' species concept. Mayr ( 1 982c: 273) and others (Hengeveld 
1 988) have added to the species definition that each species will have its own 
unique ecological niche. Simpson's "evolutionary" definition has ecologi- 
cal implications, while Van Valen (1976) also casts a species definition in 

D. Amadon & L. L. Short 20 Bull. B.O.C. 1 12A 

ecological terms. Sympatric species, no matter how similar (sibling 
species) may be assumed to have ecological (niche) distinctions (Gause's 
principle). Yet there would seem to be no theoretical reason why allo- 
patric species need differ ecologically. An insectivorous mole, Talpa, on 
one island and a marsupial mole, Notoryctes, on another, might in theory 
occupy identical ecological niches, yet they would be not merely different 
species but belong to separate sub-classes of Mammalia. No stipulation 
about ecology is needed in the species definition. 

Somewhat similar is the occasional statement that speciation has not 
been "completed" until the 2 allied taxa have acquired overlapping 
(sympatric) ranges, which derives from the simple and pragmatically 
useful fact that sympatry provides the ultimate test for the efficacy of 
reproductive isolating mechanisms. If speciation is not complete when 2 
allospecies happen to come into secondary contact, it may undergo refine- 
ment and reinforcement during parapatry and limited sympatry (e.g. the 
Passerina bunting case discussed below). Some parapatric species remain 
too similar ecologically to overlap; each of course is apt to be better 
adapted to a distinct microecotype within the main part of its range. In a 
few cases a new species may deviate so far ecologically from its immediate 
ancestors or nearest allies that overlap is out of the question, e.g. the first 
cetacean to become independent of land. 

(c) 'Recognition' species concept. Paterson (1985) concluded that the 
important element in species formation is not how individuals of a species 
avoid mating with those of other species but how they recognize indi- 
viduals of their own. The former he calls the "isolation concept" and 
thinks it needs replacing. Others (e.g. Mayr 1986) regard these as 2 sides 
of the same coin: e.g. a male moth is attracted by pheromones emitted by 
females of his own species and ignores those of others. In plants and many 
lower animals recognition consists of reacting to another individual with 
the "right chemistry." "Recognition" may be by only one sex; male Pin- 
tailed Whydahs Vidua macroura and Straw-tailed Whydahs V. fischeri 
court any small brown bird that approaches, even unrelated serins Serinus 
spp.; further the 2 whydahs maintain interspecific territories, but their 
females only breed with the "correct" males (Short & Home, pers. obs.). 
In sympatry, species are self-defining and thus are the only self-defining 
evolutionary unit. Taxonomists search for areas of sympatry between 
closely related taxa as the ultimate test of their status as species, allo- 
species or megasubspecies, and in order to gain insight into the nature of 
differences that obtain between related but allopatric taxa, the better to 
evaluate their status. 

Isolating mechanisms vary, and under stress (lack of appropriate con- 
specifics, as in captivity), interbreeding often occurs between species 
never, or very rarely, known to hybridize in the wild. Also there are 
situations involving dynamic interactions of allospecies as they initially 
come into secondary contact, in which hybrids occur commonly at first, 
and then, as sympatry increases, hybridization ceases. An example is the 
movement of the Syrian Woodpecker Picoides syriacus into the central 
European range of its allospecies, the Great Spotted Woodpecker Picoides 
major (Bauer 1957). Such biological "mistakes" (due to lack of post- 
zygotic isolating mechanisms and breakdown of pre-zygotic isolating 

Bull. B.O.C. 112A 21 Taxonomy of lower categories 

mechanisms), which may occur when the expanding species is rare and its 
potential conspecific mates are few, should not be interpreted to mean 
that the 2 taxa involved are conspecific. Sometimes, of course, a time span 
is required to be certain. In these cases strict application of Paterson's 
concept would mean that, when initially interbreeding, these taxa would 
be conspecific, but when hybridization ceased they would "become" 
species. Paterson's work will, however, bring more attention to the 
evolution of the crucial isolating stimuli involved in speciation. It should 
also prompt research on other forms of species recognition. 

The species recognition associated with reproductive isolation of 
species is not unique to that facet of biology, nor is it always successful. 
African estrildine finches have characteristic, species-specific gape mark- 
ings as nestlings, but nestlings of nest-parasitic widowbirds (Vidua spp.) 
mimic the gape markings of these estrildine nestlings, species for species, 
thus making it possible for the widowbirds to use the estrildines as foster 
parents for their own young (Payne 1982). 

Interspecific territoriality is akin to recognizing other species as if they 
were conspecific and is thus a failure to show "species recognition", or 
rather is a broadening of the "recognition" to include other species. Many 
sophisticated adaptations have evolved for recognition of prey or host 
organisms (as by parasitic wasps, and nest-parasitic cuckoos), and of 
food plants by insect larvae and their adult forms, to give only a few 
examples. Within species there may be failure of "species recognition", as 
by birds of different local song dialects, that deter interbreeding of con- 
specific individuals of different demes (Payne 1986). Females of many 
species regularly reject as mates males in subadult plumage attempting to 

The biological species definition includes all aspects of the recognition 
of conspecific mates. It is thus inappropriate to designate the biological 
species concept as the "isolation" concept, either as a substitution for it or 
to compare it with the species recognition concept. For further discussion 
of Paterson's species recognition concept see Bock (1986: 41), Coyne et al. 
(1988), Hauser (1987), and Raubenheimer & Crowe (1987). 

(d) "Cohesion species concept". Templeton (1989: 12) wrote: "The 
cohesion concept species is the most inclusive population of individuals 
having the potential for phenotypic cohesion through intrinsic cohesion 
mechanisms." He then tabulates these mechanisms. We need not repro- 
duce his table, because the final product is close to our understanding of 
the species. All species have cohesion and Templeton rightly emphasizes 
this. To some extent it partakes of the "homeostasis" mentioned at vari- 
ous points by Mayr (1963). One may note that no species, if subdivided 
spatially, is so cohesive as to prevent differentiation and eventual 
formation of a new species. Asexual "species" on the other hand are too 
"cohesive"; adaptive change can take place only by the replacement of 
entire populations, one mutation at a time. 

Templeton designated his cohesion species concept to accommodate 
both sexual and asexual populations. As discussed elsewhere, we do not 
consider this feasible. 

(e) "Phylogenetic" species concept. This was introduced by Rosen 
(1973, 1979) and followed by others including Nelson & Platnick (1981) 

D. Amadon & L. L. Short 22 Bull. B.O.C. 1 12A 

and Cracraft (1983). The phylogenetic species was recently defined by 
Cracraft (1989: 34—35) as "An irreducible (basal) cluster of organisms, 
diagnosably distinct from other such clusters, and within which there is 
a parental pattern of ancestry and descent." McKitrick & Zink (1988) 
recommended the phylogenetic species to ornithologists but gave nary 
an example of how they would apply it to any species as presently 

All more or less isolated subpopulations of a species acquire genetic 
differences, whether adaptive or by genetic drift. Founder populations 
would immediately qualify as "phylogenetic species"; their gene pool 
will differ from the larger one from which it has been drawn. Indeed 
DNA "fingerprinting", from one point of view, has reduced effective 
population size to a single individual. When such populations interbreed 
with neighbouring populations, or are capable of doing so, are they 
species? If so, one could easily find subpopulations of Homo sapiens that 
still, despite all the mixing that has gone on, qualify as "phylogenetic" 
species. Morphs of a single population may differ more than will many 
such phylogenetic species. In the White-throated Sparrow Zonotrichia 
albicollis for example, 2 morphs differ in colour, in osteology, and 
chromosomally, as well as in habitat preferences and song frequency 
(Thorneycroft 1966, 1975). Yet they are only morphs; individuals of one 
morph prefer to mate with the other. Mayr (1963: 247) listed a number of 
genera, including the lowly Asellus, in which morphs differ in habitat 
preference (and doubtless in other ways as well). 

Avise & Ball (1990) also emphasize that the number of subpopulations 
diagnosable by molecular biology or even phenotypically is enormous. 
Further, if analyzed by differing techniques or for varying goals, the 
boundaries of these subpopulations will often not coincide. The many 
well established breeds and varieties of domestic animals (dogs, pigeons, 
etc.) or cultivars and varieties of plants (roses, tomatoes, etc.) are phylo- 
genetic "species". They are kept separate by the hand of man; their 
counterparts in nature by spatial isolation. 

Presented with the males and females of a highly dimorphic species (e.g. 
the sapsucker Sphyrapicus thyroideus) in which the sexes are easily diag- 
nosed phenotypically — by the sex chromosomes and presumably (if they 
could be demonstrated) by certain genes controlling the dimorphism — 
how would one determine that they belong to the same species? Because 
they interbreed. Much molecular biology is based upon tissues of a few 
individuals. How does one know that the other individuals assigned to a 
species based on such samples belong to it? Again, because they interbreed, 
or are assumed to do so because of the phenotypic uniformity bestowed by 
interbreeding. Thus, we are again back to the interbreeding test for the 

J. Fitzpatrick, quoted by McKitrick & Zink, estimated that the Florida 
Scrub Jay Aphelocoma c. coerulescens, itself an outlier of a western species, 
might have to be divided into 2 or 3 hundred species. This may have been 
tongue in cheek but is hardly an exaggeration. This multiplication of 
species would conceal, not reveal relationships. For example, if the geo- 
graphically variable Song Sparrow Melospiza melodia were split into 30 
'species', the related, less variable, bona fide species, the Lincoln's 

Bull. B. O.C. 112A 23 Taxonomy of lower categories 

Sparrow Melospiza lincolni, and the Swamp Sparrow M. georgiana, 
would tend to be lost in the shuffle. 

Many such species would be undiagnosable in traditional museum 
practice; all old specimens would have to be identified subjectively and 
assigned to their species on geographic bases. Some of these might 
represent "temporal" species, because of biochemical evolution in the 
past 50 to 150 years after the type series and other museum material 
was collected. Fossil material would have to be ignored, or included 

We thus conclude that the proposal to call every diagnosable popu- 
lation a species is wrong in both fact and theory and would lead to chaos in 
application. That we are not overstating this point will be appreciated by 
those concerned with conservation decisions of governmental agencies, 
and the economics of conservation to the lay public, if they had to defend 
the preservation of every phylogenetic "species". 

None of the above is meant to impugn the value of genetic and bio- 
chemical research in casting light on fundamental problems. If such 
research reveals an out-and-out error, as Zink (1988) has done in the 
Pipilo crissalisjP.fuscus group of finches, and this is supported by other 
data, by all means alter the classification to correspond with the newly 
discovered facts. 

Practical considerations. How can a species be defined in terms of 
breeding behaviour when for all fossil species and many living ones, e.g. 
deep-sea fishes, we know nothing of breeding behaviour? The short 
answer is that biology is the science of life; species are populations of 
living organisms and there is no escape from this dilemma. Fortunately 
interbreeding and heredity do impart a certain uniformity to species. 
With most groups, given a mixed bag of specimens, one can sort them out 
into species with few errors. One may, to be sure, be misled by differences 
due to sex, age, castes, morphs or life stages, but this would be true 
whatever species concept was used. Once such problems have been sur- 
mounted, the identification of sympatric species usually offers no special 
problems. Some sibling species, especially among invertebrates, may, to 
be sure, remain unmasked until studied in the field or found in the 
laboratory to be inter-sterile. 

Sympatric populations that do not interbreed, or not to an extent that 
undermines their genetic integrity, are perforce species. Closely allied 
species which have only recently or partially achieved sympatry may 
interact in various ways (limited hybridization, interspecific territoriality, 
or displacement of one by the other in some areas and not in others). 

Parapatric populations present greater difficulties, but if they don't 
interbreed they are species, usually allospecies; if they do, they are sub- 
species. When limited or sporadic interbreeding occurs, the analysis 
must be more in depth; Short (1969, 1972) has presented procedures and 
guidelines for analyzing such cases. In general, if selection is reducing 
hybridization parapatrics are species, but not so if the reverse occurs. 
Often a long-term study is needed to find out, especially where parapatry 
is very limited. Most such instances are of secondary contact after 
evolution in isolation; it is doubtful whether primarily parapatric sub- 
species can advance to species status, except perhaps where there is an 

D. Amadon & L. L. Short 24 Bull. B.O.C. 1 12A 

increasingly sharp break in their ecotypes. Many parapatric species meet 
along ecological gradients, but even if the change is very gradual, the 2 
may abut sharply (e.g. see Short 1971 for 2 woodpeckers, Picoides nuttallii 
and P. scalaris, in the American Southwest). Rarely, as in the crows 
Corvus corone and 'C. cornix' of Europe (Kryukov & Blinov 1989), a 
narrow but spatially shifting hybrid zone persists; this should not be 
taken to infer that they are allospecies. In this case the narrowness of the 
zone and its shifts reflect forces of selection and environmental gradients 
that are commonly found intraspecifically, and usually are inconspicuous, 
but in this example are conspicuous (the 2 crows are all-black vs black and 
grey). For example, there is a marked shift in tail-spotting of eastern and 
western populations of the American Robin Turdus migratorius over a 
few-score kilometers in the Great Plains, whereas the crows are mega- 
subspecies, freely interbreeding throughout and are thus separated and 
yet connected by the hybrid zone. In an altitudinal transect in New 
Guinea, Diamond (1972: 27) found several pairs of species replacing each 
other abruptly, not always at the same altitudes; nor are all such pairs 
allospecies, though usually congeneric. The barbets Pogoniulus pusillus 
and P. bilineatus, not each other's nearest relative, occur sympatrically in 
some African habitats; in others there is an altitudinal replacement, and 
still elsewhere the bird of lower elevation extends to higher elevations in 
the absence of the second species (Short & Home 1988). Sometimes an 
area is found between interbreeding allospecies where neither of them 
breeds, as in the titmice Parus atricapillus and P. carolinensis in some parts 
of their ranges (Brewer 1963). 

When taxa doubtful as to subspecies or species are spatially disjunct the 
problem is more difficult. Vast numbers of populations are isolated in this 
way, on islands, in lakes, and on mountain tops. To each such case the 
taxonomist must bring all available data from study of congeneric or 
allied species and subspecies and the gaps between them; differences have 
to be sought in such possible isolating mechanisms as voice, behaviour, 
vagility, and others. Sometimes field or laboratory experiments are 
possible. Mayr (1969) provided a methodology for the evaluation of such 
taxa. Following analysis of information from all available sources, the 
taxonomist reaches a verdict as to the status of the disjunct populations. 
The verdict, to be sure, may be somewhat subjective or tentative, but an 
equally important result of the process is the enhancement of knowledge 
gained about the characteristics and biology of the organisms. 

In summary, the taxonomist working with a relatively localized fauna 
or flora will usually encounter rather few problems as to species dis- 
crimination. When working with widespread groups, especially those 
with disjunct populations in varied habitats, it is the often the rule rather 
than the exception to encounter populations near the megasubspecies- 
allospecies boundary which require a judgmental verdict. 


These are are well known terms for designating species lacking recog- 
nized subspecies (monotypic) and species having recognized subspecies 

Bull. B.O.C. 112A 25 Taxonomy of lower categories 


This term is here proposed for polytypic species none of whose sub- 
species are deemed to be approaching species status. That is, it includes 
all those polytypic species, usually a large majority in any group of organ- 
isms, that are not megaspecies. Mesospecies, like megaspecies and 
superspecies, must be evaluated at one point in time, almost always the 


Crawford-Cabral (1986) proposed this term for species composed of 
megasubspecies. He employed the megaspecies in analyzing the evolution 
and zoogeography of a group of Rodentia as represented in the fauna of 
Angola, Africa. 

Are all species that contain one megasubspecies comprised entirely of 
megaspecies? In a species such as the Northern Harrier Circus cyaneus, in 
which one megasubspecies occupies Eurasia and the other North America, 
that is obviously the case. But what of a species such as the Savannah 
Sparrow Passerculus sandwichensis, in which there is a megasubspecies 
Passerculus {sandwichensis) princeps on tiny Sable Island, off the coast of 
Nova Scotia, while elsewhere the species occupies most of North 
America, where it is separated into several lesser subspecies of the rank 
here named mesosubspecies? Almost surely, princeps, long regarded as a 
full species, is a recent post-glacial offshoot of the mainland population. 
Nevertheless, we conclude that the mainland population ranging from 
Alaska and Labrador to California should be called a megasubspecies, P. 
{sandwichensis) sandwichensis. If it and princeps were to attain species 
status, the step over the species threshold would probably not occur as a 
result of genetic changes in the mainland population, but rather in the 
small, isolated population of princeps itself, but this is not certain. For our 
purposes, this situation has been presented in oversimplified form, for 
there actually are 3 subspecies of P. sandwichensis along the coast of 
southern California and adjacent Mexico which, while not as strongly 
differentiated as princeps, nevertheless were at one time considered to be 
one or even 2 additional species. These 3 subspecies comprise a third 
megasubspecies, P. {sandwichensis) rostratus. Thus, the picture becomes 
more balanced, with a megasubspecies on or near each coast and the third 
occupying the intervening continent (Zink et al. 1991). 

In our 1976 paper introducing the megasubspecies we did in fact con- 
clude that conferring that status on one unit of a species automatically 
confers that status on the other population(s). Thus we wrote (1976: 1 63): 
"Although the term megasubspecies would often refer to a population 
occupying a small range, as on an island, this status confers like status on 
the remaining group or groups . . . of populations." 

We have minimized our use of the term "sister" taxa, because it is a 
cladistic term that most cladists restrict to only 2 taxa. Yet we know that 
there frequently are more than 2 megasubspecies in a megaspecies, or 
allospecies in a superspecies. To be sure, it cannot be demonstrated that 
the allospecies in a superspecies, when more than 2, split simultaneously. 
For all practical purposes, however, one may assume that they did; such 
assumptions are as nothing compared with those often made when fossil 

D. Amadon & L. L. Short 26 Bull. B.O.C. 1 1 2A 

taxa that diverged aeons ago are considered as sister groups. In any case 
the exact points of bifurcation are apt to be so close in time as to be 
essentially simultaneous. 

A major fault of the cladistic approach, in our view, stems from the 
very fact that taxonomic status is determined strictly by the branching 
(furcation) points, and differentiation is ignored or discounted. Yet 
there are many cases (e.g. Haffer 1974 pointed out a number of them) in 
which 3, 4 or even 5 forms evolved from a common ancestor, with their 
evolutionary history predicated (in this case) upon vicariant separation, 
such as a developing system of rivers about the Amazon, or fragmentation 
of forest by drought. If the result is 5 approximately equally divergent 
entities, we would consider all 5 as coequal mesosubspecies, megasub- 
species or allospecies depending upon their degree of differentiation and 
our judgment concerning their reproductive isolation. Were all 5 to have 
originated exactly simultaneously, their divergence from that point 
would make it extremely unlikely that their simultaneous origin could 
ever be deduced from their morphology. Even if geological data allowed 
one to construct a 'true' cladogram, this would not necessarily be useful 
(differences in time between branchings may only be several hundreds of 
years); indeed, the last 2 populations to branch, by chance alone, might 
now be more divergent than are the others that separated somewhat 
earlier. Hence cladistic analyses are liable to indicate incorrectly the 
bifurcation of the taxa. Thus it seems appropriate to treat the 5 as coequal 

Short et al. (1983) described such a case among 5 megasubspecies of 
Australian sitellas (Daphoenositta chrysoptera), all of which come together 
and interbreed, forming a 5-way hybrid zone in central Queensland. The 
determination of time factors in this divergence, as in many cases, is very 
difficult; and the analysis of their divergence through study of mor- 
phology is complicated by the evolution of 'white-headedness' in the 
megasubspecies leucocephala, which has obliterated various features of 
colour pattern useful in the other 4. The 5 taxa appear behaviourally alike 
and they are vocally not distinguishable (Short & Home, pers. obs.). Since 
all 5 hybridize inter se to the same extent, there appear to be no incipient 
isolating mechanisms in any one of them. Cracraft (1989) treats these 
sittellas very differently, using the phylogenetic species concept. He 
disregards the fact that the 5 are vocally similar if not identical, and the 
mesosubspecies that are also found among some of the 5 megasubspecies. 
Using primitive-derived character states that apparently are put forward 
ad hoc (some of his characters are affected, for example, by albinism 
in leucocephala, and for others there is simply no indication of which 
condition is 'derived'), he treats all 5 as 'species' and presents a cladogram 
of supposed relationships among the 5 for which we see no historical or 
morphological bases. In addition he ignores the extensive hybridization 
among the 5 diverse 'species'. The resulting products of interbreeding 
perforce become 'interspecific' hybrids. These occupy large areas and 
number tens if not hundreds of thousands of individuals. It is misleading 
to consider the 5 taxa as anything but coequal megasubspecies. Since the 
geological data often are unavailable or controversial in such cases, 
cladists may proceed by subjectively designating branching points based 

Bull. B.O.C. 1 12A 27 Taxonomy of lower categories 

upon morphology and degree of divergence, thus producing a branching 
hierarchy (cladogram) which may be completely in error. As noted, the 
same considerations apply to allospecies. 


We introduce this new term to designate a species that is not a member 
(allospecies) of an existing superspecies, that is, has no contemporary 
sister species. To be sure, many such species evolved as allospecies of a 
superspecies whose other members have become extinct, or, in some 
instances, may have evolved into new superspecies with their own con- 
tained allospecies. Chance events such as presence or absence of barriers, 
or differing rates of evolution, could bring about such a result. In other 
instances an isospecies may arise as a result of phyletic evolution. 


Since an allospecies is one component of a superspecies, see also the 
discussion of that unit. Having concluded that both disjunct and parapatric 
taxa should be subsumed under allopatry, we disagree with Prigogine 
(1984, 1985), who limited the term allospecies to disjunct taxa and call 
those whose ranges are in contact 'paraspecies'. 

Priogogine's 'paraspecies' is just one of many descriptive and potentially 
confusing labels that could be applied with reference only to the presence 
and amount of contact which obtains between allospecies. One could, for 
example, give 'allospecies' different names depending upon how far apart 
they are geographically, or 'paraspecies' likewise based on the extent of 
their contact, or differentiate between 'partly sympatric allospecies' as to 
the extent of their sympatry (small, moderate). Any or all of such distinc- 
tions would result in confusion. It matters greatly in analysis whether 
parapatric contact occurs along an interface 100 m, 100 km or 1000 km 
long, but such information should not be brought into definitions of taxa. 
Indeed the extent of parapatry and whether or not some sympatry occurs 
throughout a long, more or less abutting area of contact usually is incom- 
pletely known, and often is inferred from very few sites. Determination of 
parapatry requires one to verify that individuals of 2 allopatric populations 
can make contact in the breeding season. This requires that the observer is 
at the right place at the right time, particularly in cases of altitudinal 
parapatry, as non-breeders may wander out of the breeding range. We 
prefer to use 'allospecies' as above, whether the allospecies are disjunct, 
parapatric or (usually marginally) sympatric. Except that subspecies can- 
not be sympatric, we note that the same confusing terminology could be 
used for them — for example, various terms could be applied, such as 
'parasubspecies' and 'allosubspecies'; such terms we think would be ill- 
advised. It seems better to restrict the number of terms and to have them 
refer to important levels of speciation intrinsic to the taxa, and thus not 
based upon chance extrinsic factors; then they will be of broader utility. 

In parapatric allospecies, sporadic, marginal, or temporary overlap is 
probably the rule rather than the exception. Also, allospecies may be 
broadly sympatric in the off-season. Sometimes, as noted above, there may 
be a narrow zone between two allospecies in which neither occurs. More 
commonly, small, transient colonies of one or the other of a pair of allo- 
species exist within the boundaries of the other. In such situations, often 

D. Amadon & L. L. Short 28 Bull. B.O.C. 1 1 2A 

in conjunction with a patchy environment, 2 allospecies (some would say 
former allospecies) are now sympatric over considerable areas, although 
the actual contacts, because of environmental preferences, may be hardly 
greater than in more conventionally parapatric species. The Eastern 
(Sturnella magna) and Western (S. neglecta) Meadowlarks studied by 
Lanyon (1957, 1962, 1966) are sibling species, have no close relatives, 
differ greatly in song and alarm notes, and overlap over a wide zone in 
central North America. There is occasional ineffective hybridization. 
The Indigo (Passerina cyanea) and Lazuli (P. amoena) Buntings provide a 
similar example (Sibley & Short 1959), with more hybridization and 
expanding overlap; eastern cyanea now appears in pockets far into the 
western North American range of amoena. Clearly these are or were allo- 
species, and their interactions and those of similar pairs provide excellent 
object-lessons for analyzing various aspects of speciation. Such forms, 
still able to interbreed and interacting ecologically with increased sym- 
patry (ecological separation, interspecific territoriality) might be desig- 
nated 'emergent allospecies'. This could be applied as well to cases of 
expansion of one allospecies into the range of another, with hybridization 
restricted to the advancing forward line of the invading allospecies, after 
which interbreeding is much reduced or ceases, the forms being in partial 
sympatry (e.g. the woodpeckers Picoides syriacusj major mentioned above 
and the titmice Parus cyaneusj caeruleus in Europe, discussed by Short 
1969: 90-91; see Hewitt 1989). 

Another remarkably complex case is afforded by 2 wood-warblers, 
Vermivora pinus and V. chrysoptera, which occur in patchy habitat over 
much of eastern North America (Gill 1987). They are sympatric in some 
areas and allopatric in others. Though the species' identities are not 
undermined, the 2 hybridize fairly freely, producing an array of hybrid 
phenotypes, 2 of which are so frequent and so distinct that they were 
described as species. Vermivora pinus is moving northwards, usually 
replacing chrysoptera y but with at least one pocket of the latter "left 
behind" in somewhat atypical habitat (Freeh & Confer 1987). As a further 
complication occasional individuals learn the song of the 'wrong' species. 

The behavioural interactions, general similarity, and occasional 
hybridization in such pairs demonstrate that they are allospecies. Careful 
analysis and weighing of evidence is necessary in determining their status 
and what they reveal about the dynamics of speciation and allied pro- 
cesses. Expanding allospecies with overlap but still some hybridization 
may be approaching the limit of allospecies, but with 'backward' 
shifts still possible, perhaps due to man's persistent modification of the 

The attention given to such taxa reflects their importance. One diffi- 
culty in considering partly sympatric pairs to be (still) allospecies is that in 
sympatry they may be mixed, and possibly confused with, species that are 
still interacting 'sexually' and ecologically in one way or another, but 
which are beyond the point where they can be properly called allospecies. 
Broadly overlapping congeneric species, perhaps formerly allospecies, 
may interact to some degree, and even species representing different 
genera can interact strongly, appearing like emergent (congeneric) allo- 
species. For example 2 wrens, Thryomanes bewickii and Troglodytes 

Bull. B.O.C. 1 12A 29 Taxonomy of lower categories 

aedon, still hold interspecific territories, even though they are usually 
placed in different genera (Root 1969). Some might prefer to use Ripley's 
(1945: 338) term "interspecies" pair or group in such cases until their 
interactions have been well-studied and their relationships are clarified. 

As noted earlier, the analysis of disjunct, closely allied taxa is difficult 
and sometimes subjective. Still, the gamut of possible shades of relation- 
ships is the same for disjunct, parapatric and partly sympatric sister taxa; 
what differs critically among them are the possibilities for interactions, 
and these determine the amounts and kinds of data they can provide, and 
the techniques that are available for studying them. 


Sibling species are ones that are difficult to distinguish phenotypically, 
such as the Eastern and Western Meadowlarks mentioned above. They 
will almost certainly belong to the same genus, but may not necessarily be 
the most closely related species within the genus, though that will often be 
the case. The classic example is of the fruit flies Drosophila pseudoobscura 
and D. persimilis, which can be separated phenotypically only by refined 
statistical analysis of measurements from large samples. Yet these 2 are 
completely cross-sterile and hence ipso facto species. Such sibling species 
are being unmasked commonly among insects; they exist but in far 
smaller numbers in vertebrates. The term is subjective and largely one of 
convenience and there is no 'test' or absolute criterion for sibling species. 
They may be either sympatric or allopatric, but the sympatric ones 
receive the most attention because they immediately pose problems as to 
how such at least superficially similar species can coexist. Allopatric sib- 
ling species are less apt to be detected unless it is found by chance that 
they are intersterile. In a few cases among birds, for example the many all- 
black crows and ravens of the widespread genus Corvus, there are 
numbers of both allopatric and sympatric sibling species. 

Many sibling species evolve as an end result of divergence in isolation, 
and only later (sometimes) become sympatric; their antecedents, ranging 
from demes to megasubspecies, must be even more difficult to detect. 
The antecedent populations would not fulfill the requirement for formal 
subspecies since they would probably not be 'visibly different'. As a 
practical matter, it seems unwise to name such 'proto-sibling species' 
when they are suspected. There is a special challenge to the taxonomist to 
evaluate allopatric populations very carefully in groups well known to 
have sibling species, for example, among birds: Corvus; larks, Alaudidae; 
tyrant-flycatchers, Tyrannidae; and bulbuls, Pycnonotidae. 

The 8 terms here advocated for various species-level taxa are not all 
mutually exclusive. A species may be monotypic or polytypic (but not 
both). A polytypic species may be either an isospecies or a mesospecies 
or a megaspecies. An isospecies cannot also be an allospecies, but an iso- 
species or an allospecies can also be a monotypic species, or a mesospecies, 
or a megaspecies. In theory, any of the others could be a sibling species. 

16— GENUS 

Higher classification is based upon the grouping of species in clusters of 
varying degrees of relationship, and is thus a scheme of hierarchies in the 

D. Amadon & L. L. Short 30 Bull. B.O.C. 1 12A 

Linnaean system of classification (genus, tribe, subfamily, etc.)- These 
hierarchies are a result of evolution, with its speciation, adaptive radiations 
and extinctions. Thus higher classification is based on reality; but it also has 
a subjective element in that each cluster of species is, to a degree, unique. It 
is a matter of opinion as to how closely related a group of species must be to 
constitute a genus or a group of genera to constitute a family. Some species 
are so distantly related to any contemporary ones that they are best left in 
monotypic genera. For 'splitters' (taxonomists using many small genera) 
or 'lumpers' (those employing very broad genera) one can only counsel 
moderation. The genus has as its only function (aside from reducing the 
number of species names required), that of indicating groups of related 
species, but it must not be so inclusive as to impinge on the next higher 
category (tribe, subfamily, family). Nor can the number of categories be 
arbitrarily established; above we mentioned one, the tribe, not used by 
Linnaeus. The genus and subgenus, however, are 'official' categories, 
with established rules for their nomenclature. 

The binomial system does have one serious flaw: changes in the genus' 
name affect both biologists and the general public. Yet new information as 
to a species' relationships may make nomenclatural changes mandatory; 
honest differences of opinion may do the same, e.g. one taxonomist being 
more impressed by certain morphological, behavioural or other peculi- 
arities of a species, perhaps considering it as a monotypic genus, than is 
another who allows for more differences among congeneric species). 
Again, one can only recommend holding changes to a minimum; official 
check-lists, revised occasionally, help. More drastic solutions, such as 
using very broad genera and conducting the finer details at the subgenus 
level (Amadon 1966a) or using a mononomial system (Michener 1964) 
have met with little interest. Numerical systems may, to be sure, be 
used with computers (Little 1964), but names are needed also: it is easier 
to remember a hundred names, even Latin ones, than 4 or 5 numbers 
replacing a name. 

One should attempt to keep the criteria for genera and other higher 
categories consistent across groups and time. This has heuristic value in 
that, e.g., a list of the species in an ecotype will contain genera that are 
roughly equivalent for plants and animals. Likewise fossil biotas, which 
often consist of a mixture of extinct and living species, can be meaning- 
fully compared as a unit or with other biotas, and included with them in 

Perhaps it is worth stressing the obligation of the systematist to place 
his studies in perspective by considering the next higher and next lower 
category to that with which he is dealing. That is, species of a genus ought 
not to be studied or revised without considering the taxonomy of related 
genera, and the final results ought to take them into account. A genus (or 
species, or family) should not be studied, as it were, in a vacuum. Like- 
wise, although political or economic factors sometimes force a narrow 
focus upon a taxonomic investigation, studies that are geographically 
restricted (to a state, country or region), although the taxa involved are 
widespread outside that restricted area, should sometimes be postponed. 
Caution is especially advised when working with a taxon at the fringe of its 
range, or taxa which are at the periphery of the range of the group to which 

Bull. B.O.C. 112A 31 Taxonomy of lower categories 

they belong. If avoidable, a speciose tropical genus should not be revised 
if one can study in detail only a handful of its species which marginally 
penetrate an adjacent temperate region. 


The subgenus is a formal category and if one recognizes subgenera in a 
genus then all of its species should be assigned to one subgenus or 
another, according to their affinities. A systematist revising a genus con- 
taining some little known or problematic species may prefer to avoid this 
formal category and use the informal species group; then species pre- 
senting such problems may, so to speak, be left 'dangling' without the 
necessity of assigning them formally. It is better to employ subgenera 
than to oversplit genera. In groups in which many genera were named 
that now seem superfluous, such names are often available for subgenera. 
It is unwise to use subgenera in some genera of a family but not in other 
equally diverse ones, though if some are much better known than others 
this may ensue. A few taxonomists go to the extreme of decrying generic 
'splitting', meanwhile flooding the literature with subgenera. 


As defined — a genus containing more than one species. 


The genus is defined as a group of species; hence a genus with but one 
species seems like a contradiction in terms. Nonetheless, some species, 
indeed considerable numbers in certain groups, are so distinct and 
lacking in close relatives that they must be admitted as monotypic genera. 
If we had a complete fossil record some of them would be found to have 
contained other species now extinct. Indeed many monotypic genera are 
relicts, but some of them may have contained but one species for a very 
long time, e.g. Gingko, Latimeria and Sphenodon. Still others are probably 
the end products of phyletic evolution and never contained other species. 
Among birds, Balaeniceps or Rhynochetos might be candidates. Finally, 
during adaptive radiations, species may evolve with relative rapidity, 
thereby producing monotypic genera that may or may not later bud off 
additional species. Thus, at any point in time some species have very close 
relatives, others only very remote ones, while the majority fall between. 


This term was coined by Amadon (1968) but the concept has been 
employed by others (e.g. Diamond 1972: 305). Many genera consist of 
a single superspecies and are, for some biogeographical purposes, 
equivalent to a single species. Thus the skimmers, Rynchops, a super- 
species with 3 species, 1 in Africa, 1 in India, and 1 in the Americas, are so 
similar and specialized that it is unlikely that sympatry will ever ensue; 
this genus is quasi-monotypic. 


The species group might be regarded as an informal, un-named sub- 
genus. Because it is informal, not all the species in a genus have to be 
assigned to a species group and indeed the information is often lacking to 
do so. With further data, species groups in a genus may be replaced by 

D. Amadon & L.L. Short 32 Bull. B.O.C. 11 2A 

formal subgenera, or this may be deemed unnecessary. Obviously, use of 
the species group does not burden the memory with more names (usually 
a species group is referred to by the specific name of one of its best known 
or widespread species). The purpose of both categories, of course, is to aid 
in understanding relationships and lines of evolution, especially in 
species-rich genera (see Mayr & Short 1970: 102-103). 

Paramount is the point that the species in a group are more closely 
related, often considerably more closely related, to one another than is any 
of them to any other species in the genus outside the group. It is implicit 
that there are gaps between species groups. In very large genera, it 
sometimes may be desirable to set up species groups within subgenera. 

HafTer ( 1 986a) has more rigorously, and we feel unnecessarily, redefined 
species groups to equate them with putative former superspecies whose 
component species are actually or potentially sympatric. This would 
severely limit the use of species groups because allopatric species (that 
were formerly all allospecies of a superspecies) can evolve further in iso- 
lation to the point at which their relationships are those of a species group 
(or, with one or more other sympatric or allopatric species, they may form 
a species group). Also a superspecies, or several superspecies, may form a 
species group together, or along with, one or more isospecies. Extinctions 
of species or allospecies may leave isospecies that are taxonomically some- 
what isolated in their genus, though their relationships with other iso- 
species and superspecies may be sufficiently close to include them in a 
species group. 

The barbet genus Trachyphonus contains 5 species interrelated as 
follows: (a) a species group erythrocephalus-margaritatus-darnaudii, of 
which the first 2 make a superspecies, while darnaudii is a megaspecies; 
(b) another megaspecies purpuratus; and finally (c) a mesospecies, 
vaillantii (Short & Home 1985a,b, 1988). This illustrates the use of a 
species group in a way that would not be possible under Haffer's ( 1 986a, b) 
proposal, by which we feel much is lost in encumbering and narrowing 
the use of 'species group'. 

22 — SUPERSPECIES (see also discussion of allospecies) 

The allospecies of a superspecies are more closely allied to one another 
than to any other species. Some genera, subgenera or species groups 
consist of a single superspecies, but many contain species not so intimately 
related. Allospecies are often the equivalent of the cladist's 'sister species' 
(or for some, e.g. Cracraft 1989, 'sister megasubspecies'). 

In formal taxonomic treatments the use of brackets to indicate super- 
species is recommended (Amadon 1966b). In other contexts this may be 
accomplished by using footnotes (A.O.U. 1983), by the use of braces 
(Short 1982), by connecting allospecies with hyphens (Diamond 1972: 
321 ), or by the use of superscripts (Amadon & Bull 1 988). 

In listing allospecies of a superspecies, the first named allospecies 
does not always appear first, because of relationships, primitive-derived 
sequences, or geographical conventions. In some local or regional publi- 
cations, not all of the allospecies in a superspecies may be listed. Still, it is 
often useful to know that a species has allospecies elsewhere. For example 
in a list of the bird species of Africa Haliaeetus [vocifer] indicates that 

Bull. B.O.C. 112A 33 Taxonomy of lower categories 

vocifer has one or more closely related species (allospecies) elsewhere (in 
this case a species in Madagascar). 

The designation of superspecies is often tentative. The Indian and 
African elephants do not form a superspecies, but without a fossil record 
that might not be so obvious. Question marks may be used to indicate 
doubt, or one may say "species 'X' and species 'Y' may constitute a 
superspecies". Such qualifications do not detract from the utility of the 
concept (Amadon 1966b, Mayr & Short 1970). 

Haffer (1986b) has rigorously subdivided superspecies into 'First 
Order' superspecies (those we have discussed above); and 'Second Order' 
superspecies (or 'megasuperspecies'). The second order superspecies 
contain either 2 (or presumably more) of his first order superspecies, or a 
mixture of one (or more) first order superspecies with one (or more) 
species not part of a first order superspecies, i.e. with what we term 
isospecies. While every attempt to clarify and denote relationships is to be 
applauded, there is greater subjectivity in Haffer's approach; for example, 
one must guess about extinctions of former allospecies. We suppose one 
could go further, to 'Third Order' superspecies, and so on, but this would 
seem to compound the subjectivity at several levels, perhaps exponen- 
tially, with greater difficulty in distinguishing second order and third 
order superspecies, and even more potential for errors. We realize that 
many isospecies evolved as allospecies of superspecies whose sister allo- 
species became extinct. Proving this would indeed be difficult, as in the 
case of Haffer's (1986b, Fig. lc) example of a second order super- 
species formed from 2 first order superspecies, each of which apparently 
had suffered the extinction of one allospecies. By overly striving to be 
precise, Haffer has unduly restricted a more broadly useful terminology, 
coupled with the addition of greater subjectivity, and we think his 
categorizing of superspecies is not practical for general use. To be sure, 
specialists intensively studying a limited cluster of taxa may find it 
worthwhile to group them in various ways. 

There has been an unfortunate tendency, evident, e.g. in Hall & 
Moreau (1970) and Snow (1978) to place all well-marked, congeneric, 
allopatric taxa into superspecies. This 'overinflation' of the superspecies, 
effectively to the level of the species group, has been criticized by Vande 
weghe (1988: 2550), indicating the crucial need to use all available infor- 
mation in making taxonomic decisions involving allopatric taxa. It is the 
task of the taxonomist to evaluate carefully all related allopatric taxa to 
determine whether they are monophyletic, and whether relationships are 
at the level of megasubspecies, superspecies, or species group. Faulty 
assignment of level (equivalent to 'upgrading' or 'downgrading') is wrong, 
no matter what the level, whether done intentionally (persons concerned 
about the conservation status of taxa may do this), or unintentionally 
(through failure to analyse appropriately the available data). Allopatry 
alone does not place a taxon in any one of these categories. 


This is the concept that is usually called a 'zoogeographical species' — 
one in which isospecies and superspecies are equated as biogeographic 
entities. That is, individual allospecies are not tallied separately. Since the 

D. Amadon& L.L. Short 34 Bull. B.O.C. 112A 

concept applies equally well to plants, in which they would be called 
'phytogeographic units', we suggest that biogeographic be used to cover 
both. Further, 'species' is somewhat misleading in this context, because 
superspecies, of course, are groups of species, not single species. We 
therefore believe the word 'unit' to be preferable. 

As an example, assume that a chain of islands was colonized by 2 species 
of a family, the 2 not closely related (i.e. they represent different genera). 
Assume further that one of them is now a superspecies with 5 allospecies, 
each on its own island, while the second is still monotypic. If all the 
allospecies are tallied, it conceals the important fact that the family in 
question has colonized these islands only twice. Biogeographic units thus 
are useful in comparative studies of the diversity of different regions, and 
continents, as well as diversity of different groups within and between 
regions (see Mayr & Short 1970: 5). 

In his check-list of the Pipridae and of the Cotingidae and elsewhere 
Snow (1979, see footnotes) equated 'zoogeographical species' with 
'superspecies', citing Mayr & Short (1970). The latter, however, as we 
do here, treated zoogeographical species (or 'units') as including not 
only superspecies, but also non-allospecific species (isospecies). We feel 
that our usage and the distinction between zoogeographical units and 
superspecies have considerable heuristic value. 


The interchange of genes (e.g. 'conjugation' in Paramecium) 
apparently arose fairly early in the history of life and in higher organisms 
became sexual reproduction. The latter conferred such immense advan- 
tages by increasing heritable variability and hence adaptability that 
it has been dominant ever since (Vrijenhoek 1990). Nevertheless, some 
monocellular organisms (some bacteria) and a few advanced forms of life 
reproduce exclusively by asexual means. Most of them are plants and 
result from polyploidy; vegetative reproduction is much easier in plants 
and permits such sterile individuals to survive. Parthenogenic popu- 
lations among animals are rarer, except for 'castes' in some social insects, 
but these are irrelevant here. Polyploids or sterile hybrids between 
species of animals have little chance of survival, but a few parthenogenic 
populations of lizards and other groups have managed to do so. Such 
instantaneously produced species, whether plant or animal, usually 
survive, when they do so, in raw, disturbed habitats (whether naturally 
so, or by humans), where competition is less. 

Many species of plants, known by chromosome counts to have arisen 
by polyploidy, later again reproduce sexually. Occasionally fertile indi- 
viduals do occur, and so great is the premium on genetic exchange that 
gametic reproduction has become re-established. 

Are asexually reproducing populations or clones to be called species? 
Our preference would be to use some such term as 'pseudo-species' or 
'quasi-species'. Nevertheless, so much literature, especially botanical, 
uses 'polyploid species' that we see little hope of a change. Hence one 
accepts a second major category of species to be called 'Asexual' or per- 
haps better 'Agametic' species. Other species are then Sexual or Gametic 
Species. The latter are so much more important and successful (except 

Bull. B.O.C. 112A 35 Taxonomy of lower categories 

perhaps in some bacteria, viruses and the like) that the term species, 
without qualification, may be taken to refer to those in which an exchange 
of gametes occurs. If confusion arises, a simple alternative would be 
to agree that 'species' in quotation marks always refers to asexual 


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Address: Dean Amadon & Lester L. Short, Department of Ornithology, American Museum 
of Natural History, Central Park West at 79th Street, New York, New York 10024, 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 39 G. F. Barrowclough 

Biochemical studies of the higher level 
systematics of birds 

by George F. Barrowclough 

Received 16 April 1992 


The use of biochemical methods in avian systematics has a significantly 
long history, with early reports involving immunology dating back almost 
100 years (e.g. Nuttall 1904); consequently, these methods are nearly as 
old as the Bulletin of the British Ornithologists' Club. 

Nevertheless, the quantity of early research was minimal and the results 
not particularly influential until a major increase in such studies began in 
the 1960s. By that time the technique of protein electrophoresis had been 
developed sufficiently to allow rapid surveys of samples of blood and 
egg-white, and it quickly replaced the earlier use of serological and 
immunological techniques (e.g. the research programme of workers such 
as Erhardt 1930, Irwin & Miller 1961, Mainardi 1963 and Stallcup 1961). 
Rapid developments in medicine and molecular genetics were quickly 
integrated into research programmes in biochemical systematics. During 
the same period of time, advances in analytical methods, along with philo- 
sophical insights into the nature of phylogenetic inferences, had resulted 
in rapid changes in systematic practice. Thus, the advances in biochemi- 
cal technology and analysis used in avian taxonomy during the past 
30 years, reviewed here, have been remarkable. The earlier, largely 
immunological work on avian systematics was reviewed previously by 
Sibley etal. (1974). 

In considering the achievements of biochemical systematics, important 
distinctions arise concerning the taxonomic level of the problem. 
Microtaxonomic or microevolutionary studies are inquiries which are 
aimed at elucidating the genetic structure of populations and problems of 
the origin of species; whereas macrotaxonomy is the study of the related- 
ness and phylogeny of species and higher taxa. Until now, the success of 
molecular methods at these 2 levels has differed considerably. The quality 
and impact of biochemical studies of macrotaxonomy are the subjects of 
this review. Biochemical studies of microevolution in birds were the 
subject of earlier reports (Barrowclough 1983, Evans 1987). 


General proteins 

Some electrophoretic experiments on avian proteins were reported as 
early as the 1930s (Landsteiner e£<z/. 1938); however, McCabe& Deutsch 
(1952) reported on comparative electrophoretic mobility of egg-white 
proteins from 37 species representing several orders of birds, and it was 
this work that led Sibley, his graduate students and post-doctoral associ- 
ates to begin a major research programme in electrophoresis, principally 

G. F. Barrowclough 40 Bull. B.O.C. 1 12A 

aimed at elucidating higher level avian relationships. The work involved 
first paper, and later starch-gel electrophoresis of egg-white proteins fol- 
lowed by treatment with a general protein stain. Additional studies 
involved haemoglobins, and blood plasma proteins, eye lens proteins, and 
feather keratins. The utility of the technique lies in the detection of 
mobility differences among proteins based on their electrical charge 
and the shape of the molecule; thus, similarities and differences among 
taxa are documented. Two major monographs (Sibley 1970, Sibley & 
Ahlquist 1972) summarized many of these results. 

Statements about the Sturnidae are typical of the results reported in 
these works. For example, egg-white electrophoretic patterns of 10 
species of starlings in 7 genera are cited in the passerine volume; the 
patterns of Sturnus and Lamprotornis were found to differ in a major 
component protein and those of Sturnus and the woodswallow Artamus 
appeared to match well. Thus, Sibley was able to conclude, among other 
things, that the first 2 genera may not be closely related and that the 
Artamidae are one of the most likely relatives of the Sturnidae. 

Techniques for separation of proteins became more sophisticated in 
the latter 1960s and early 1970s and, at least in Sibley's laboratory, 
starch-gel methods were replaced by acrylamide gels and then isoelectric 
focusing in acrylamide. The amount of energy, resources and talent that 
went into this research, in a number of laboratories, over 2 decades was 
enormous; the quantity of data produced was voluminous. Moreover, the 
problems addressed were of genuine taxonomic interest. Unfortunately, 
however, it is clear in retrospect that this research programme produced 
few lasting accomplishments. This was due to 2 factors: the absence of 
quantitative methods of analysis and insufficient informative characters. 
Neither of these problems was understood by the systematics community 
at the time of the work, nor was the failure peculiar to one research 

It is now generally recognized that in order to infer a phylogeny, it is 
necessary to use cladistic or other phylogenetic methods that can dis- 
tinguish between derived and primitive similarity (e.g. Wiley 1981). This 
recognition only became widespread in the 1970s, after much of the gen- 
eral protein work had been eclipsed by newer techniques. In principle, 
phylogenetic methods could have been applied to egg-white and other 
studies of proteins. For example, if homology of specific proteins on the 
gels could be established from species to species- — a serious problem with 
total protein staining methods — -alternate mobilities could be treated as 
alternate character states and analysed in a phylogenetic framework. In 
fact, this line of reasoning later was pursued by workers such as Brush & 
Witt (1983) and Knox (1980). 

For example, in a study of the relationships of several species of 
Pelecaniform birds, Brush & Witt determined the electrophoretic 
mobility of feather keratins under several pH conditions; they computed 
genetic distances among the taxa, based on the sharing of bands among 
species, using general protein staining. Phylogenetic trees were computed 
based on the genetic distances. The trees were generally similar in that 
congeneric species tended to stay together, but the precise branching 
patterns depended on both the pH of the electrophoretic experiments and 

Bull.B.O.C. 112A 


Biochemical studies 


Figure 1 . The details of evolutionary branching patterns cannot be recovered given too few 
characters or when branching events are too close in time. Left: Hypothetical evolutionary 
tree for 10 species with 10 character changes, randomly distributed in time, indicated by 
bars. Right: Maximally informative tree that can be inferred from character data shown on 

the algorithm used to infer the tree. Such results indicate the dependence of 
pattern identity on pH and the sensitivity of tree topology to assumptions 
in the algorithms about constancy of rates of evolution. 

The second serious problem with the general protein approach was the 
number of characters available for analysis. In a starch-gel, egg-white 
studies might indicate a half dozen or so easily visualized proteins. For 
avian haemoglobins, the number is less. If one's objective is to work out a 
fully resolved phylogeny for the taxa of interest (i.e. no nodes of the tree 
generating more than 2 lineages), then there must be at least one mobility 
change in one character between every pair of nodes of the actual tree 
(Fig. 1). Consequently, there must be more total character states in the 
data set than there are taxa in the study. Moreover, if the amount of 
evolutionary time between nodes of the actual tree was short for some of 
the branches, then the probability of a character state change for that 
branch is also small. Therefore, a large number of characters are necess- 
ary for there to be a significant chance of a change occurring along the 
short branches (e.g. see Lanyon 1988). For electrophoresis of egg-white, 
the number of potential character states is insufficient to produce a fully 
resolved phylogenetic tree for more than a few taxa (Table 1). With iso- 
electric focusing, the number of distinguishable proteins and mobility 
states increases, but then homology problems also are accentuated. 

Once these 2 major problems are acknowledged, it is apparent that 
either many more characters must be made available in order to attack the 
major problems of higher level systematics (for example, the relation- 
ships of the families of birds) or one must be content with lesser 
goals: identifying clades rather than working out fully resolved trees or 
allocating a taxon of dubious affinities to one of several suspected groups. 
It was at this reduced level of resolution that egg-white studies achieved 
some limited success. For example, Sibley (1968) was able to show that 

G. F. Barrowclough 


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Bull.B.O.CAHA 43 Biochemical studies 

Zeledonia belonged somewhere in the New World 9-primaried oscine 
assemblage rather than with either the wrens or thrushes, as previously 
had been thought. 


Lewontin & Hubby (1966) introduced the technique of electrophoresis 
followed by specific enzyme staining to a general audience of evolutionary 
biologists and systematists. This represented a major breakthrough: it 
made many more characters available than previously and was a relatively 
inexpensive technique. The ability to examine the mobility states of 
single enzymes greatly reduced the homology problem present in total 
protein staining. Furthermore, the number of different enzyme stains 
developed for medical clinicians and human geneticists meant that 30 or 
40 characters were available, some of which might show 3, 4 or more 
different mobilities. 

By the late 1970s and early 1980s a substantial number of workers in 
avian systematics were using allozyme techniques. Initially much of this 
research involved somewhat higher level systematics, for example, 
working out the relationships of species within genera and genera within 
families (e.g. Barrowclough & Corbin 1 978, Avise et al. 1 982, Gutierrez et 
al. 1983). However, the quantity of this work was soon superseded by 
studies of intraspecific variation, for example, hybrid zones (e.g. 
Barrowclough 1980, Corbin et al. 1979), differentiation among intro- 
duced populations (e.g. Baker & Moeed 1987), differentiation among 
vocal dialects (e.g. Baker 1982), and variation among variable taxa that 
might represent either species or subspecies (e.g. Zink 1988, Johnson & 
Marten 1988). These studies of intraspecific variation did have major 
impact on avian systematics in the broad sense: in North America they led 
to changes in opinion about species status of a number of taxa (e.g. see 
Johnson & Marten 1988). More generally, they led to a general interest 
in avian evolutionary genetics and a more quantitative understanding of 
the population genetic structure of birds (Rockwell & Barrowclough 
1987). The impact of the higher level studies, however, was considerably 

Early on in the allozyme research enterprise it became clear that there 
was considerable heterogeneity in the degree of variability and rates of 
differentiation among the various genetic loci routinely analysed with 
allozyme electrophoresis (e.g see Evans 1987). Thus, although it might 
appear that 40 loci and 100 or more alleles were available for studies of 
higher level relationships, in fact this was a major overestimate. Some 
loci, for example the malate dehydrogenases, were so uniform that little 
variation was detected at the level of orders of birds; such loci were conse- 
quently of little value for studies of phylogeny within families or genera. 
Other loci, for example the non-specific esterases and adenosine 
deaminase, varied so much that they were useless for studies much above 
the species level — so many alleles were present that results were domi- 
nated by alleles unique to each taxon (autopomorphy) and convergences 
(homoplasy) rather than shared derived mobility states (synapomorphy). 
Consequently, at any given taxonomic level, the number of informative 
character states was often quite small and true cladistic studies produced 

G. F. Barrowclough 44 Bull. B.O.C. 1 12A 

polychotomies — unresolved phylogenies — because there were no charac- 
ter states defining many of the possible nodes. This was the same 
limitation found in the earlier studies involving general protein staining. 

A second major problem with many allozyme studies at higher levels 
was a general failure of investigators to take on real taxonomic problems. 
In the late 1 970s, when the techniques first became available, a smattering 
of general studies was perhaps justified in order to determine the useful- 
ness of the technique, the level at which it was useful, etc. Unfortunately, 
however, the allozyme work never matured to the point where workers 
consistently investigated problems such as phylogeny of all or even the 
major part of a taxon. Thus, one might find a study of a few thrushes 
representing a small fraction of a taxonomic problem. Studies such as 
Gerwin & Zink's (1989) phylogeny of 8 of the 9 species of hummingbirds 
in the genus Heliodoxa were in a minority. At higher taxonomic levels 
even less was done; thus, the taxonomic awareness and intensity found in 
Sibley's earlier work with general protein staining was not generally 
present in researchers using the newer technique. In the cases in which 
researchers pushed the technique in useful directions, some interesting 
results were produced. Kitto & Wilson (1 966), for example, found that one 
allele at the mitochondrial MDH locus defined the order Charadriiformes 
and a second allele identified the major clade of swifts plus humming- 
birds. Likewise, Matson (1989) found the expression of a testes-specific 
lactate dehydrogenase that was a synapomorphy for Columbiformes. 
Such limited, but useful, results were, in retrospect, about all that should 
have been expected from the technique at the familial and ordinal levels. 

Allozyme electrophoresis had its lasting impact at lower taxonomic 
levels. First, the potential at higher levels was not widely appreciated and 
pursued and, second, given that the number of potential character states 
was always destined to be small at any taxonomic level, fully resolved 
phylogenetic trees were not really a possibility. The few interesting 
results that were achieved at higher levels did not have major influence on 
practical systematics; the results were often not new, the taxonomic 
sampling was too restricted, or the results were ambiguous. For example, 
Johnson et al. ( 1 988) examined most of the species in the family Vireonidae 
using allozyme electrophoresis. Their results indicated long, separate, 
evolutionary histories for several lineages of these birds; however, the 
detailed phylogenetic relationships inferred for the taxa varied depending 
upon the algorithm used to analyze the data. Thus, many of the details 
necessary to produce a new taxonomic treatment of the family remained 


Microcomplement fixation 

The immunological response of an organism to an antigen is based on 
many aspects of both the composition and conformational structure of the 
molecule in vivo. Thus, although the biochemical nature of the reaction 
itself is still the subject of intense investigation, it is nevertheless clear 
that more information is being assayed than just charge and size, as in 
electrophoresis. Less information is available than in direct amino acid 

Bull. BO. C.112A 45 Biochemical studies 

sequencing of the protein, but the cost is a fraction of that technique. 
Consequently, microcomplement fixation was used in a few labs for a 
decade or so in the late 1970s and the 1980s. This method allowed one to 
obtain a quantitative measure of the similarity of proteins based on the 
immunological response of the antibodies produced against a protein 
from one taxon on the homologous protein of the other taxon. 

The major limitation of the method is that the technique of necessity 
yields information on the overall immunological distance between 2 
organisms for a given protein; individual character information is not 
available. Thus, any phylogenetic analysis would require distance 
methods. These are less reliable than character methods because of their 
inability to identify specific apomorphies and homoplasies and, unless 
one assumes the protein evolves in a clocklike fashion, at the very least 
immunological experiments must be performed on all combinations of 
taxa; that is, a complete matrix of information is required. This makes the 
technique more and more expensive as the number of taxa, N, increases 
because the number of requisite experiments becomes of the order of N 2 . 
Consequently, the technique would be most useful for working out 
relationships of a few species or allocating a species of unknown affinities 
to one of two or three higher taxa. For an investigator working out the 
relationships of approximately 175 avian families, other techniques 
would make more economic sense and ultimately involve less time. 

Allan Wilson and his associates worked with the technique for approxi- 
mately 15 years. In this period of time they used 4 major proteins (albu- 
min, lysozyme, ovalbumin and transferrin) and addressed problems at 
several levels in a number of avian groups. Of particular interest to Wilson 
were the galliform birds; in part this was due to the availability of substan- 
tial quantities of proteins for birds frequently kept in aviaries. However, 
in spite of the effort directed at the problem, the results that could be 
obtained were restricted by the necessity to do reciprocal experiments, 
obtain a complete N x N matrix of data, and confirm results with alternate 
proteins. For example, Prager & Wilson (1976) reported on a study of 24 
species from 4 families of galliforms and 1 and 2 representatives each of 
13 other orders of birds. The resulting phylogenetic tree (based on a 
distance analysis) was surprisingly similar to some recent results of Sibley 
& Ahlquist (1990); nevertheless, the sparsity of the taxonomic sampling, 
the publication in a non-ornithological journal, and the inconsistencies 
with the then current ideas about relationships, led to the paper having 
little impact on avian systematic thought. 

Peptide mapping 

Electrophoretic experiments are capable of separating homologous 
proteins that differ in charge, isoelectric point and, to a lesser extent, 
shape. Nevertheless, it was recognised that 2 proteins with identical 
electrophoretic mobility could still vary in amino acid sequence. Before 
amino acid sequencing became available, information on sequence differ- 
ences could only be obtained by indirect methods. One briefly popular 
technique was to cleave a purified protein into peptides with enzymes 
having highly specific activity (e.g. trypsin) and then compare the result- 
ing peptides using electrophoresis and chromatography. Although a 

G. F. Barrowclough 46 Bull. B.O.C. 1 12A 

substantial number of characters can be obtained per protein with this 
method (20 or more for ovalbumins), establishing homology of the 
individual peptides can be a difficult problem. In addition, the technique 
is time-consuming and expensive; it never became very popular. Of the 
little published work, the best such study was Corbin's (1968) work 
on pigeons of the genus Columba; however, that analysis predates the 
adoption of modern phylogenetic methods. Thus, his results were sum- 
marized in statements concerning the degree of similarity of taxa rather 
than as a phylogenetic tree. 

Peptide mapping, like all the techniques listed thus far, involves an 
indirect method for revealing character differences resulting from amino 
acid sequence differences. By the mid-1960s it had become possible, 
albeit laborious, to obtain the actual amino acid sequence. 

Amino acid sequencing 

A large protein may consist of a string of as many as several hundred 
amino acids, each of which can take on, in theory, one of 20 states. Thus, 
the sequence data for just a few proteins has the potential to yield a 
vast quantity of systematic data. Moreover, by the time amino acid 
sequences began to appear in numbers in the mid-1970s, numerical 
phylogenetic techniques were also becoming available. Consequently, 
by picking proteins evolving at an appropriate rate, investigators might 
have used this technique to solve most of the major problems in higher 
level avian systematics. Many researchers realized this, but the tech- 
nique never became labour or cost effective. Allan Wilson mentioned 
(pers. comm.) in 1977 that he thought sequencing the lysozyme of a 
single species was a good Ph.D. project. Thus, given approximately 175 
families of birds and 2000 genera, the higher level systematics of birds 
might have been worked out in a few generations of researchers (see 
Table 1). 

In fact, however, amino acid sequences were worked out only for a 
small number of taxa for a few proteins because the Wilson lab at the 
University of California at Berkeley was the sole major proponent of 
the technique among avian systematists. For example, one report from 
Wilson's lab (Jolles et al. 1 979), reported lysozyme sequences for 9 species 
of birds; a chachalaca (Cracidae) was found to be quite distant in its 
sequence from other galliforms, including a guineafowl. Biochemical 
physiologists also sequenced a number of avian globin genes, but those 
data were never synthesized and brought to the attention of avian 
workers. The amino acid sequence data eventually produced were too few 
to have a real effect on avian systematics. 


All protein methods, including amino-acid sequencing, are unable to 
reveal some potentially useful character state data because proteins are 
translated from DNA sequences that contain more information than 
do the corresponding amino acid sequences. For example, the 2 DNA 
sequences TTA and CTG both code for the same amino acid, leucine. If 2 
taxa of birds had these alternate sequences, protein techniques would fail 

Bull.B.O.C.WlA 47 Biochemical studies 

to detect the differences. In theory, then, studies of DNA offer the poten- 
tial for more characters, hence a greater chance of finding state changes 
along short branches, thus more resolution, etc. All protein methods can 
be viewed, in fact, as indirect attempts to get at DNA sequence infor- 
mation. As soon as the relationship between DNA sequences and protein 
coding was understood in the 1950s, it was realized that DNA analysis 
would be the ultimate tool of molecular systematics. However, DNA 
sequencing was preceeded by less direct techniques for developing this 
rich source of information. 

DNA-DNA hybridization 

Shields & Strauss (1975) first reported on the application of a method 
for comparing the overall DNAs of species in their study of some New 
World finches. In this method an index to the similarity of the DNAs of a 
pair of species is found by monitoring the melting temperature of hybrid 
molecules of DNA formed in the laboratory. In general the more similar 
2 DNA sequences, the higher the melting point; this can be precisely 
measured under controlled conditions. A general review of the technique 
can be found in Sibley & Ahlquist (1990). The approach was adopted 
by Sibley and his colleagues in the early 1970s and a major research 
programme undertaken that has ultimately involved comparisons of 
thousands of individuals of hundreds of species. 

The results of this research have been quite controversial, largely 
because of concerns about the method of analysis of the data. Besides 
problems of data reduction peculiar to the Sibley & Ahlquist laboratory 
(Lanyon 1992), the method itself inevitably produces only a measure of 
the overall distance between 2 taxa. Thus, there are no character data to 
analyze; consequently, methods of phylogenetic analysis that are free of 
assumptions about evolutionary rates ought to be used and these necessi- 
tate a complete matrix of intertaxon distances. Once again this causes the 
amount of work involved to increase as the square of the number of taxa. 
For practical reasons, then, DNA-DNA hybridization studies must 
involve a small number of taxa or involve dubious assumptions about 
evolutionary rates. The advantage of the technique was that it does 
examine DNA; hence in the 1980s it represented a novel dataset, and it 
involves a large part of the total genome, not just a single gene or class 
of genes (e.g. enzymes). However, contrary to statements of some 
proponents, the latter advantage does not entirely vitiate problems of rate 
differences. It was argued (e.g. Sibley & Ahlquist 1983) that, because a 
very large number of genes were being analyzed, rate differences among 
genes would average out to a grand mean and produce an overall constant 
rate of evolutionary change. This would make the data easier to collect 
and analyze because a complete data matrix is not always essential for 
clocklike distances. It is true that the law of large numbers works to the 
technique's advantage for one of the sources of variation — average differ- 
ences in evolutionary rates among genes within individuals. However, 
other sources of variation are not affected by this averaging; these include 
changes in rates of substitution across the entire genome due to: 1 .) demo- 
graphic events, such as fluctuating population sizes; 2.) relative efficacy of 
DNA repair mechanisms in alternate lineages; 3.) differing mutation or 

G. F. Barrowclough 48 Bull. B.O.C. 1 1 2A 

fixation rates in taxa with differing life histories or generation times. 
Thus, a clocklike pattern of evolutionary change is an empirical issue, to 
be demonstrated, not postulated. 

To date, the best study using DNA hybridization in birds was 
Sheldon's (1 987) analysis of the herons (Ardeidae). About half of the total 
species were treated, but only 13 of the herons were included in a com- 
plete data matrix. In part this was because each pair of species was repli- 
cated 10 times. Nevertheless, the study was more complete than many 
biochemical studies in that all the major lineages were represented; thus 
the results were of real interest to systematists. However, the study indi- 
cates something of the limitations of the technique. The necessity to 
replicate a complete data matrix several times in order to determine the 
relationships of the major lineages of a moderate sized family took a 
considerable amount of time and effort. This study is near the upper limit 
of a reasonably sized investigation using DNA-DNA hybridization; it 
comprised Sheldon's Ph.D research. 

Bledsoe's (1988) DNA-DNA study of 9-primaried oscines was also a 
Ph.D. project. It involved a complete 13x13 matrix of taxa. Of necessity, 
however, only a few genera of this very large assemblage could be 
included; thus, the results do not have immediate effect on the details of 
avian taxonomy. Rather, they suggest interesting problems to follow 
up. The same might be said of the massive data produced by Sibley & 
Ahlquist. Because of the widespread concerns about the details of the 
analysis, the lack of complete data matrices for most of the published 
material, and concerns about distances data in general, there is scepticism 
in the systematics community about the interpretation of these data (e.g. 
Cracraft 1987, Gill & Sheldon 1991, Lanyon 1992). It is unlikely much 
can be done about this, however; producing a complete data matrix for 
175 avian families is not feasible with the technique. Unquestionably 
some of Sibley & Ahlquist's suggestions will be confirmed by future 
studies; but ornithologists will look to other techniques for support for 
these hypotheses. 

Restriction enzymes 

Genetic discoveries in the 1970s and 1980s made available a battery of 
enzymes that cleave specific sequences of DNA; for example, the restric- 
tion enzyme EcoRl only cuts the sequence GAATTC. In a large sequence 
of DNA, such 'recognition sites' will occur at a particular position in some 
taxa and, due to evolutionary changes, not in others. With a large enough 
number of these enzymes and a sufficiently long sequence of DNA, a large 
number of character states — the cleaved sites — will be available for 

An appreciable amount of research using this technique has been 
underway for only about 5 years. In practice, most workers have used 
mitochondrial DNA in order to reduce the number of sites to a reasonable 
number (nuclear DNA is so extensive that a large number of recognition 
sites invariably are found; the resulting number of fragments visualized on 
a gel is so great that homology becomes a problem). Analyzed cladistically, 
such data, if sufficient in number, can yield fully resolved branching 
diagrams for problems of taxonomic interest. Relatively expensive, the 

Bull. B.O.C. 1\2A 49 Biochemical studies 

technique has been used only in a few labs; it is so recent that much of the 
work to date has consisted of exploratory studies aimed at determining the 
usefulness of the method at various taxonomic levels (e.g. Avise & Zink 
1988). A major impact on avian systematics is only beginning to be felt 
(e.g. Zink & Dittmann 1991, Gill & Slikas 1992). However, the technique 
is already being superseded by a newly available method for direct 
sequencing of DNA. 

DNA sequences 

Until a few years ago, actual sequencing of DNA was an expensive, 
elaborate procedure involving genetic cloning in vectors, etc. However, 
the development of the polymerase chain reaction (PCR) for gene ampli- 
fication and rapid and efficient sequencing technology has now made it 
possible to produce large quantities of specific sequences of DNA from 
relatively large numbers of individuals in a reasonable period of time. 
Thus, it is already feasible to perform a phylogenetic study involving the 
DNA sequence of more than 900 base pairs for more than 20 taxa (e.g. 
Richman & Price 1992). If even 10% or 20% of such bases are variable, 
then an appreciable amount of information will be available for phylo- 
genetic inference. Because each new sequence can be compared with all 
previous ones, for the same gene, the amount of work required in a study 
increases only as the number of species, N. The potential of this tech- 
nique is such that it is rapidly being adopted by avian systematists 
throughout the world. 

At present only a few genes are being sequenced; the most widely used 
is the mitochondrial cytochrome-b gene. Various domains of this gene 
appear to evolve at different rates — reflecting the functional constraints 
of alternate portions of the translated protein. The gene has already 
proved useful for systematics and ecological problems; for example, using 
cytochrome-b sequences, Richman & Price (1992) were able to produce a 
fully resolved (completely dichotomous tree) phylogeny for 22 species of 
sylviid warblers. They then used the tree to interpret patterns of morpho- 
logical variation among 8 species of Phylloscopus warblers sympatric in 
the Himalayas. 

Various other genes, mitochondrial and nuclear, are known to have 
greater (D-loop, ATPase8) and lesser (cytochrome-c oxidase) rates of 
evolution than cytochrome-b (Arctander 1991). It is feasible to choose 
such alternate genes, with their varying rates of nucleotide substitution, 
as a function of the taxonomic problem of interest. Thus, the technology 
is essentially available today to produce voluminous data on avian re- 
lationships at many levels — from populations within species, to species 
within genera, to families within orders (e.g. Birt-Friesen et al. 1992, 
Johnson & Cicero 1991, Edwards et al. 1991). The number of characters 
potentially available is not likely to be limiting except for vanishingly 
short branches. Numerical algorithms to deal with the quantity of 
data in a phylogenetic manner are more of a problem, but computer 
power is rapidly improving. It does not take great bravery to predict that 
a decade from now many of the major problems of avian systematics, 
and certainly the relationships of the families, will be solved using this 

G. F. Barrowclough 50 Bull. B.O.C. 1 12A 


The past century has seen a growing amount of research in the higher 
level systematics of birds using biochemical techniques, but particularly, 
and rapidly, over the past 30 years. Up to the present time, however, the 
results have not lived up to expectations, and it is only in recent years that 
a sufficient understanding of the various problems have emerged. In par- 
ticular, results have been limited due to an absence of analytical method, a 
lack of sufficient numbers of characters, and, more recently, a failure to 
work on genuine systematic problems. 

In Table 1 , the efficacies of 8 major biochemical techniques are evalu- 
ated in terms of 3 typical problems in avian systematics. I have taken as 
the basis for comparison the doctoral dissertation project as the unit of 
time; this is convenient as many results have been obtained through such 
projects, providing a natural standardization; expense might have been an 
alternative. The simplest problem considered is the allocation of a diffi- 
cult species to a family of birds; for example, what are the affinities of the 
Hoatzin, Opisthocomus? Second, what is the phylogeny of the species in a 
large genus or a small family, e.g. the Alcidae? Third, is the dominant 
problem of avian higher level systematics the relationships among avian 
families? Thus, for example, electrophoresis with general protein staining, 
intensively used in the 1960s, yielded too few characters and pre-dated 
quantitative analytical methods of phylogenetic inference; in retrospect 
this and other techniques were inappropriate for resolving many of the 
problems on which they were used. This same limitation was more or less 
true of allozyme work. Microcomplement fixation, an immunological 
technique, and amino acid sequencing were the first techniques available 
that were at all appropriate for the highest level avian systematics, but 
both had real limitations. Amino acid sequences were too time consuming 
and expensive to obtain. The immunological technique, while useful at 
the level of intrafamilial relationships, has N 2 complexity. Consequently, 
a problem involving 175 species is 7 2 times as difficult as a problem with 
25 species. The recently used technique of DNA-DNA hybridization has 
the same complexity. 

During the 1 970s and 1 980s, many workers in avian systematics shifted 
away from macrotaxonomy questions to the study of microevolutionary 
processes; in part this may have been due to the failure or expense of 
previous techniques. However, the long sought goal of molecular system- 
atics, DNA sequences, has become feasible in the past 5 years. The tech- 
nique offers access to numerous characters useful at all taxonomic levels, 
and algorithms for data analysis are becoming widely available. For the 
first time (Table 1), a technique is available that is appropriate and 
economical for solving the major problem in avian systematics, the 
relationships of the families of birds. 


I am grateful to C. Griffiths, J. Groth and P. Sweet for helpful comments on this 
manuscript, and to P. Sweet for the preparation of Fig. 1 . 


Arctander, P. 1991. Avian systematics by sequence analysis of mtDNA. Proc. Intl. Ornithol. 
Conr. 20: 619-628. 

Bull.B.O.CAHA 51 Biochemical studies 

Avise, J. C, Aquadro, C. F. &Patton, J. C. 1982. Evolutionary genetics of birds. V. Genetic 

distances within Mimidae (mimic thrushes) and Vireonidae (vireos). Biochem. Genet. 

20: 95-104. 
Avise, J. C. & Zink, R. M. 1988. Molecular genetic divergence between avian sibling 

species: King and Clapper Rails, Long-billed and Short-billed Dowitchers, Boat- 
tailed and Great-tailed Grackles, and Tufted and Black-crested Titmice. Auk 105: 

Baker, A. J. & Moeed, A. 1987. Rapid genetic differentiation and founder effects in 

colonizing populations of common mynas ( Acridotheres tristis) . Evolution 41 : 525-538. 
Baker, M. C. 1982. Vocal dialect recognition and population genetic sequences. Amer. Zool. 

22: 561-569. 
Barrowclough, G. F. 1 980. Genetic and phenotypic differentiation in a wood warbler (genus 

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Address: G. F. Barrowclough, Department of Ornithology, American Museum of Natural 
History, New York, NY 10024, U.S.A. 

© British Ornithologists* Club 1992 

Bull. B.O.C. Centenary Suppl. 1 992, 1 1 2A 53 W. J. Bock 

Methodology in avian macrosystematics 
by Walter J. Bock 

Received 9 March 1992 


Interest in avian macrosystematics has a history that extends for over 200 
years from the early beginnings of systematics. Analysis of this history is 
in itself a most interesting subject as the advances made over the past 200 
years have been irregular and plagued with pitfalls, stops and starts, with 
periods of great activity interspersed with little to no work. An adequate 
historical review of avian macrosystematics does not exist, but cannot be 
undertaken here. 

Macrosystematics includes 2 separate and quite different explanatory 
systems, with distinct modes of group hypotheses and disparate patterns 
of testing against secondary hypotheses and finally against empirical 
observations (Bock 1973: 391, 1977, 1981). These are: (a) explanations 
about the evolutionary relationships of organisms expressed in systems 
of biological classification; and (b) explanations about the pattern of 
phylogenetic branching expressed in a phylogenetic diagram. In both 
explanatory modes, groups of organisms are recognized, but the nature of 
these groups differ sharply from one another (see below). To be complete, 
the findings of any macrosystematic analysis should be expressed both in 
a biological classification and in a phylogenetic diagram, each of which 
provides different types of information about the organisms. Many 
systematists, e.g. cladists, argue that these 2 modes of explanation 
represent the same information; consequently, cladistic classifications are 
redundant with diagrams of phylogenetic branching. This approach is 
rejected by evolutionary systematists as lacking important information 
contained in evolutionary classifications. Both modes of explanation are 
equally important, but here I limit my discussion to the formulation and 
testing of biological classifications, with the clear realization that this is 
only one part of avian macrosystematics. 

During the past 200 years, considerable advance has been achieved in 
recognizing many of the major groups of birds (orders and families), 
although considerably less understanding has been reached in clarifying 
the relationships of these groups to each other. Many, indeed most, of 
the groups we recognize today, such as waterfowl (Anatidae), pigeons 
(Columbidae), parrots (Psittaciformes), woodpeckers (Picidae), among 
many others, are accepted by all ornithologists. In this way, some natural 
groups of birds can be said to be robust, that is, recognized by all workers 
regardless of their approach to systematics, or which characters are 
used in the analysis, and how well or poorly the characters have been 
analyzed. Pigeons are pigeons, parrots are parrots, gulls are gulls, owls 
are owls. Even the novice in avian systematics will assign species correctly 
to these robust groups. The real test of our understanding of avian 
macrosystematics — especially our comprehension of the methodology 
used to formulate and especially to test, classifications — comes with the 

W.J.Bock 54 Bull.B.O.C. 112A 

many unresolved general systematic problems in birds, such as: what are 
the relationships of the Hoatzin (Opisthocomus)?; are the Piciformes a 
natural group?; are the palaeognathous birds and the ratites monophyletic 
groups?; what are the relationships of the Pteroclidae?; or of the Coliidae?; 
or of the Trogonidae?; or of the Cathartidae?; or of many families of 
oscine birds within this suborder? It is naive to claim that even the best 
methodology will solve all taxonomic problems as some avian groups 
may prove stubbornly resistant to the best attempts to resolve their 

The past 40 years have proven to be a period of exceptionally high 
activity in avian macrosystematics, following a half century of sluggish- 
ness. During these 40 years, greatest emphasis has been placed on the 
discovery of new taxonomic features to supplement traditional morpho- 
logical features used for the previous 150 years. Initially, considerable 
emphasis was given to behavioural features, but this interest was short 
lived. Subsequently, more and more attention was given to chemical 
features, such as egg-white proteins (Sibley 1970, Sibley & Ahlquist 
1972), blood proteins, lipids in secretions of the uropygial gland (Jacob, 
see Jacob & Ziswiler 1982), comparisons of total DNA content of the 
nucleus (Sibley & Ahlquist 1990), and finally sequencing of M-DNA 
(Shields & Helm-Bychowski 1988, Avise 1986) and of nuclear DNA. 

Considerable attention has been given to whether a phenetic, a cladistic 
or an evolutionary approach provides the best biological classifications. 
Here, I restrict myself to consideration of a proper methodology for 
testing taxonomic hypotheses about groups, including the necessary 
analyses of taxonomic properties of characters. This methodology should 
be common to all approaches to classification, be they phenetic, cladistic 
or evolutionary. 

During the past 40 years, considerable attention has been given to 
the analysis of large sets of taxonomic characters using sophisticated 
computer-based numerical techniques (generally some type of corre- 
lation analysis such as PAUP or Hennig86), in the attempt to obtain the 
best and most "parsimonious" classification. However, what has been 
almost completely lacking during the past 40 years are considerations 
of the analysis of the taxonomic characters themselves, both in theory and 
in actual studies. These methods include how different types of group 
hypotheses are tested against hypotheses about taxonomic properties of 
characters, how these character hypotheses are tested themselves against 
empirical observations, and the role of functional and adaptive analyses in 
character analysis. Theoretical papers such as Cracraft (1981a), Raikow 
(1985), Cracraft & Mindell (1989) and practical systematic studies, such 
as Cracraft (1974), Bledsoe (1988), Cracraft (1981b), Gauthier (1986), 
Swierczewski & Raikow (1981), Simpson & Cracraft (1981), Sibley & 
Ahlquist (1990), and McKitrick (1991), offer sweeping conclusions on 
the relationships and classification of birds, based, indeed, on intensive 
comparative description of old and new taxonomic characters and on 
elaborate computer-based analyses of data sets of these characters. But 
one will search in vain in these papers for any biological understanding of 
these taxonomic characters. In spite of the sophisticated methods used for 
describing some of the characters and of the excellent computer-based 

Bull. B. O.C. 112A 55 Avian macrosystematics 

methodologies, these studies continue to be founded on character ana- 
lyses predating Darwin's 'On the Origin of Species' and the subsequent 
acceptance of evolutionary concepts by biologists. Herein lies, in my 
opinion, the basic failure in avian macrosystematics. 

One part of the solution lies in the clarification of the nature of bio- 
logical classifications — what they are and for what purposes they are 
used — and the type of scientific explanation involved in establishing 
them. The other and perhaps the most significant part of the solution lies 
in the erecting of a methodology for the formulation of hypotheses at 
several levels and their testing, with careful attention given to the proper 
empirical observations used in the last step of the testing procedure. This 
methodology must be in close agreement with detailed aspects of accepted 
evolutionary theory, not just with a simplistic statement that organisms 
have evolved. If the evolution of phenotypic features results from selec- 
tive demands arising from the external environment, i.e. is adaptive or 
coupled with adaptive evolution of other features, then the methods of 
macrosystematics must depend on functional-adaptive studies. The criti- 
cal roles of these studies are in testing taxonomic properties of characters 
against empirical observations and in the establishment of degrees of 
confidence in the conclusions of these tests. These are topics on which I 
have devoted considerable effort and have published a series of papers 
(Bock 1959, 1965, 1967, 1969, 1973, 1977a, 1977b, 1978, 1979, 1980, 
1981, 1988, 1989a, 1989b, 1990, 1991, Bock & de W. Miller 1959, Bock & 
von Wahlert 1965, Szalay & Bock 1991), to which the interested reader is 
referred for a full theoretical foundation of the points made in this paper. 

It should be stressed that the ideas developed in these papers on 
hypotheses formation and testing and on the essential role of functional/ 
adaptive studies are valid regardless of the approach to classification. 
Although these ideas are dependent on a full understanding of evolution- 
ary theory, they are not restricted to evolutionary classification, but are 
equally valid for cladistic and phenetic approaches to classifications. 
However, a clear distinction must be made between a cladistic approach 
to classification and the so-called cladistic method of analysis; I consider 
the latter to be scientifically invalid (Bock 1981: 15). A distinction should 
also be made between cladistic and phylogenetic methods. Moreover, the 
various computer-based methods for formulating classifications on data 
sets, such as Hennig86 or PAUP, will work equally well with characters 
analyzed using these methods, because they depend only on an ordered 
character set and do not depend on how one has determined the 
information about the characters and their states. 

These theoretical concepts will be illustrated by the use of several 
actual examples, in which more convincing conclusions have been 
reached using the methods mentioned above when compared with studies 
in which functional-adaptive investigations were not used. 


The concept and use of classifications in any science, including biological 
classification, are generally poorly understood in spite of their widespread 
use. Simply put, classifications are heuristic systems, no more and no less 

W.J. Bock 56 Bull.B.O.CAUA 

(Warburton 1967, Bock 1973), but none the less valuable, and careful 
attention should therefore be given to their form and testing. As heuristic 
systems, classifications can be constructed according to any set of ideas or 
criteria depending on how the classification is used. For classifications to 
be 'natural' or 'general reference systems', they must be formulated 
according to the primary theory of the appropriate science. Evolutionary 
theory is the foundation for biological classifications, and hence they 
should reflect evolutionary theory as closely as possible. By evolutionary 
theory, I do not mean simply that living organisms have changed over 
time, rather I mean all aspects of this theory (e.g. "the five theories of 
evolution of Darwin"— Mayr 1982: 505, 1991: 36-7) including a detailed 
understanding of the causes and processes of evolutionary change. As 
emphasized by Hennig (1966: 8), it is complete nonsense to argue, as did 
Rosen et al. (1979), that a "natural order exists in nature", e.g., that 
"nature's hierarchy exists" independently of any theory and can be 
discovered with the use of a theory-free methodology. 

As heuristic systems, classifications have a number of important uses 
(Warburton 1967, Bock 1973). Primarily, biological classifications 
provide the foundation for comparative studies in biology (see Bock 
1989a for a discussion of the principles of comparison in biology). 
They summarize succinctly known empirical information about diverse 
organisms, and form the basis of information retrieval systems; but classi- 
fications are emphatically not information retrieval systems themselves 
and one cannot obtain directly from any classification the information 
used 'to construct', or better said to test, that classification. In addition, 
classifications serve as the foundation on which efficient and meaningful 
hypotheses can be generated about biological organisms for further 
research and testing, e.g. the prediction of unknown characteristics. The 
best natural classifications are those which permit the best summarization 
of known information and the best prediction of unknown features in 
diverse organisms. 

It must be emphasized strongly that a classification and a phylogeny of 
a group, e.g. the class Aves, are not synonymous, but are 2 different and 
valuable methods to record conclusions reached in systematic analyses. 
Efforts by some systematists, e.g. cladists, to render these 2 systems of 
representation redundant to each other simply results in losing useful 
knowledge about the group; and as I have argued elsewhere (Bock 1977b, 
1981), methods for testing classifications and for testing phylogenies 
differ distinctly from each other. Hence, a well carried out macro- 
systematic study should include in its conclusions both a clearly 
presented classification and a phylogenetic diagram. 

Classifications and phylogenetic diagrams are related explanatory 
systems in biology and hence it is necessary to inquire into types of 
explanations involved in both classifications and phylogenetic diagrams. 
Many theoretical biologists and philosophers of science have claimed that 
evolutionary biology, being concerned with the history of organic life, is a 
strictly historical endeavour. A few philosophers have even claimed that 
because it is concerned only with the history of life, evolutionary theory 
is not part of science proper. Some systematists (mainly cladists) 
have claimed that all explanations in evolutionary biology, including 

Bull. B.O.C. 112A 57 Avian macrosystematics 

systematics, are strictly nomological (Gaffney 1979, Platnick 1979, 
Platnick & Gaffney 1977) in a desperate effort to bring their work in line 
with Popperian concepts. Both positions are extreme and invalid, since 
evolutionary biology involves both nomological-deductive explanations 
(N-D E) and historical-narrative explanations (H-N E); I have outlined 
the distinctions between them in several papers (Bock 1981, 1988, 1991). 
Explanations associated with biological classifications (relationships 
between organisms) and with phylogenetic diagrams (branching of 
phylogenetic lineages) are clearly historical-narrative and as such are 
covered by the methods for formulation and testing H-N E, which 
depend on the N-D E within evolutionary biology including the known 
causes and processes of evolutionary change. 


If biological classification should reflect all aspects of evolutionary theory, 
so must the entire methodology of hypotheses formation and testing, 
including the predictions generated from various hypotheses and their 
eventual testing against empirical observations under the tenets of H-N 
E. First it is necessary to distinguish between group hypotheses and 
character hypotheses (Bock 1977b, 1981). 

Group hypotheses in macrosystematics are of 2 types which differ 
sharply from one another both in their formulation and testing. The first 
are classificatory hypotheses about taxa which express the evolutionary 
relationships of the constituent members within a formal hierarchical 
system under the conventions accepted for evolutionary classification. 
This formal classification is a Linnaean hierarchy and the rules for recog- 
nizing the taxa are those that maximize simultaneously the postulated 
degree of evolutionary change and the sequence of phylogenetic branch- 
ing of these groups. The taxa, once recognized, must be monophyletic in 
that the members of the taxon are descendants from a single ancestral 
taxon at the same or lower categorical rank. 

The second type of group hypotheses are phylogenetic hypotheses 
about phyla (singular = phylon; see Bock 1977b: 877, 1981: 13) which 
express the pattern of phylogenetic branching within a formal phylo- 
genetic diagram under the conventions accepted for these diagrams, 
namely successive dichotomous forks as advocated by Hennig (1966). 
Groups in this phylogenetic diagram are phyla which are closed 
descendent groups. The phyla, once recognized, must be holophyletic 
( Ashlock 1971), that is a group which includes the ancestral species and all 
descendent species. Phylogenetic hypotheses about groups can express 
ancestral-descendent relationships in addition to sister-group relation- 
ships. For an analysis of phylogenetic hypotheses about groups and their 
testing see Bock (1977b, 1981), as I restrict myself herein to classificatory 
hypotheses about groups. 

Sequence of hypotheses formulation and testing 

Although most taxonomic investigations are usually pursued with little 
to no attention given to the actual sequence of hypothesis formulation 
and testing, a definite order of these activities should be used in a 
formal analysis of macrosystematic methodology, and this sequence 

W.J. Bock 58 Bull.B.O.CAUA 

should be followed in written presentations (see Bock 1985a, 1985b, Bock 
& Morony 1 978b, Bock & Biihler 1 990, for examples). This sequence is as 

a) Formulation and statement of classificatory hypotheses about groups 
These statements express hypotheses about the composition and evo- 
lutionary relationships of taxa which are monophyletic groups in the 
broad sense. Classificatory hypotheses should be explicit and stated at the 
beginning of a paper; they are within the realm of H-N E. Classificatory 
hypotheses are of the sort: is the genus Diglossa as recognized in Peters' 
Check-list monophyletic?; are the diverse species of flowerpiercers 
members of 2 distinct and not closely related genera, Diglossa and 
Diglossopis y within the Thraupinae (Bock 1985a)?; do the palaeognathous 
birds constitute a monophyletic group?; do the ratites constitute a mono- 
phyletic group (Bock & Biihler 1990)?; is the genus Promerops a member 
of the Meliphagidae (Bock 1985b)? Such hypotheses can be answered in 
the affirmative or negative. 

Group hypotheses are easy to formulate, but this is not the important 
element in macrosystematics. The skill required is to be able to dis- 
tinguish between those hypotheses worthy of further consideration for 
serious testing and those which can be disregarded for the present time. 
There are no reasons to consider seriously at this time, for instance, the 
testable hypothesis that the genus Struthio is a member of the family 
Corvidae. Moreover, one does not just formulate well-tested hypotheses, 
an expression used by some avian systematists. Rather, one should pro- 
pose hypotheses worthy of consideration and then test them sufficiently 
so that they can be regarded as well-corroborated and usable as foun- 
dations for standard classifications and sequences. There are, of course, 
perfectly good classificatory hypotheses about groups which may not be 
worthy of consideration and testing at the current time because of an 
insufficient knowledge about the taxonomic features needed to test them. 
Formulating any classificatory hypotheses about particular groups and 
undertaking a comparative investigation of some feature do not of 
themselves provide a convincing basis for reaching sound conclusions 
about the classification of these taxa. Not all features are useful taxonomic 

b) Formulation and statement of character hypotheses about taxonomic 
properties of features 

Secondary hypotheses about taxonomic properties of features are used 
to test the classificatory hypotheses about groups, and must be suited 
to the group hypotheses being considered — the secondary ( = character) 
hypotheses must constitute valid tests regardless of the 'goodness' of the 
test. Valid tests of group hypotheses are those which relate predictions 
arising from the group hypotheses through the secondary character hy- 
potheses to empirical observations according to the detailed stipulations 
of evolutionary theory. 'Good' tests are valid ones with a high ability 
to distinguish between correct and incorrect hypotheses — that is, possess 
a high resolving power to separate correct and incorrect answers. 
Taxonomic properties of features are those relative attributes of features, 

Bull. B.O.C. 112A 59 Avian macrosystematics 

such as homology, plesiomorphy versus apomorphy, arising from the 
evolutionary history of the group. Hypotheses about taxonomic proper- 
ties of features are H-N E. At some point within the test of such 
hypotheses must be appropriate N-D E, namely, the fundamental 
nomological aspects of evolutionary theory (see Bock 1981, 1988, 1991). 

The only valid character hypothesis known to me for the testing of 
classificatory hypotheses about groups is homology (Bock 1977b, 1981, 
1989b). Homologous features (or conditions of the features) in 2 or more 
organisms are those that stem phylogenetically from the same feature 
(or condition) in the immediate common ancestor of these organisms 
(Bock 1989b: 331). Hypotheses about homologues must always include a 
conditional phrase that describes the nature of the homology — i.e. the 
attributes of the feature in the immediate common ancestor. Conditional 
phrases are arranged into hierarchies - horizontal ones for the purposes of 
this analysis dealing with classificatory hypotheses. 

Several widely used tests of classificatory hypotheses are, however, 
invalid (Bock 1981) and include those using criteria such as parsimony, or 
internal consistency or logic, or parallelism with changes in ontogeny, or 
distribution of character states in taxonomic groups. The last includes the 
almost universally used method of out-group comparison in cladistic 
analysis. This method is directly circular (Bock 1981: 15) because the test 
of the character hypotheses depends on the distribution of the character 
states in taxonomic groups and these character hypotheses are then used 
to test classificatory hypotheses about the same taxonomic groups. 

The only valid test of hypotheses about homologues involves all forms 
of shared similarities between the presumed homologues; observations of 
these similarities comprise the objective empirical observations required 
in testing scientific hypotheses (Bock 1981, 1989b). Similarity of pre- 
sumed homologous features is assumed to represent 'ancestral similarity', 
namely, the attributes present in the feature in the immediate common 
ancestor of the several organisms being compared, and which remained 
unchanged during evolution of the different lineages from the common 
ancestor. It must be emphasized that the defining criterion of homology is 
phylogeny and that phylogeny is defined in terms of evolution. Similarity 
is used to test hypotheses about homologous features, not to define the 
concept of homology. The difference between phylogeny and similarity is 
the distinction between the criterion used in defining theoretical concepts 
and that used in testing hypotheses about objects in nature presumably 
corresponding to the theoretical concepts. Only after being tested posi- 
tively using empirical observations of similarity, are homologous features 
in diverse organisms then used to test classificatory hypotheses about taxa 
containing these organisms. No circular reasoning is involved in this 
analysis as frequently argued. Homologous features are not ascertained 
and tested by the phylogeny of groups and then used to test the phylogeny 
of these groups. 

c) Establishing degrees of confidence 

After testing and accepting hypotheses about the homology of features 
with properly stated conditional phrases, the next step is to estimate a 
degree of confidence ('goodness') for each homology, since the only valid 

W. J. Bock 60 Bull. B.O.C. 1 1 2A 

test of hypotheses about homology distinguishes between correct and 
incorrect ones very poorly. If the hypothesis about the homology has 
been accepted, then the determination of a degree of confidence does not 
increase its acceptance. As is well known similarity of features in diverse 
organisms can be homoplastic as the result of independent origin and 
convergent evolution. Estimation of a degree of confidence in a particular 
homology is a probability measure, considering concepts of Bayesian 
probability, and depends largely on approximation of the probability that 
the features involved originated and underwent similar evolutionary 
change independently. These estimates must be based on the accepted 
principles of evolutionary change and on the evolutionary changes 
possible in the class of features containing the homologues, that is, how 
bones evolve, how muscles evolve, etc. Essentially, they depend on func- 
tional and adaptational analyses of the features, with the postulation of 
possible transformation sequences (that is, phylogenetic reconstruction 
series) based on these analyses. 

Estimating the degree of confidence in accepted hypotheses about 
taxonomic properties of features is that aspect of systematics usually 
termed 'weighing of characters' or 'ascertaining the taxonomic value of 
characters'. Most discussions of character weighing, although inherently 
reasonable, have never been placed on a sound theoretical basis. Moreover, 
evaluation of degrees of confidence must be done apriori, not a posteriori, to 
the use of these character hypotheses in testing group hypotheses. 

The degree of confidence will depend strongly on the complexity of the 
actual feature, its relationship with factors of the external environments 
and hence with selective demands, and whether the feature is appearing 
or being lost in evolution, etc. If the homologous feature is a simple one, 
such as the brown colour of the plumage in different species of sparrows 
which serves as protective colouration, then one may well assign it a very 
low degree of confidence. If the feature is a complex one, such as the 
Weberian sound-transmitting ossicles derived from vertebral processes 
in a number of fresh-water teleost fishes, one is justified in estimating a 
high degree of confidence. Generally, the degree of confidence is higher 
in homologues which have appeared and are becoming more complex 
during their evolution than in those which are disappearing or becoming 
simpler. Many of the considerations given by taxonomists about criteria 
for homology (e.g. Rieger & Tyler 1979) or to an estimate of the 
taxonomic values of different characters (Hecht & Edwards 1977) are 
actually methods establishing confidence in accepted conclusions about 

Estimation of these degrees of confidence is an absolute requirement in 
macrosystematic analysis because so many apparent homologues have an 
exceedingly low probability of being correct. It is simply not valid to 
use equally all successfully tested homologies in the testing of group 
hypotheses. Homologies with low degrees of confidence have little or no 
value in tests of group hypotheses, contrary to the beliefs of many 
systematists. Unfortunately no studies have been done using the concepts 
of decision theory on the contribution of homologues with varying 
degrees of confidence in accepted group hypotheses. However, some 
rough estimates suggest that even several hundred independent 

Bull. B.O.C. 112A 61 Avian macrosystematics 

homologues, each having a degree of confidence of less than 10% will 
provide a poor test of a group hypothesis. A much smaller number of 
independent homologues, perhaps 10 or even fewer, each having a degree 
of confidence of over 90% may provide a very convincing positive test of a 
group hypothesis. The long lists of untested postulated homologues given 
in numerous taxonomic papers may appear convincing at first glance, but 
they become far less impressive when one realizes that no attempt has 
been made to state the hypotheses of homologies clearly, let alone to 
establish degrees of confidence in the homologues involved. Generally 
little work is required to demonstrate that most of the homologous 
features in the long lists possess low levels of confidence. 

d) Testing of group hypotheses 

Each classificatory hypothesis about groups is tested against a number 
of separate character hypotheses about homology, each of which has been 
tested against empirical observations completely independently of the 
others. As already indicated, increase in the degree of confidence in group 
hypotheses is gained with increase in the number of tests against different 
homologous features possessing a high degree of confidence. 

Each empirical test of a character hypothesis about homologies must 
be absolutely independent of all others. Otherwise the different 
homologues will not provide independent tests — they are redundant — as 
stressed by Bock (1977, 1981, 1989b). Examination of the criteria for 
homology advocated by some authors (e.g. Remane 1952), demonstrates 
that some are either not independent of other homologues or are not 
independent of the group hypothesis being tested. Homologues tested 
with such criteria would not provide additional independent valid tests of 
the group hypothesis and hence would not increase the confidence in the 
correctness of the group hypothesis. Continued testing of a group 
hypothesis against more and more character hypotheses possessing low 
degrees of confidence simply does not add to the confidence already 

The single major defect in many papers on macrosystematics lies in 
the use of character hypotheses possessing low degrees of confidence 
for testing group hypotheses. Close examination of the large number of 
taxonomic characters cited by Gauthier (1986) supporting his conclusion 
that birds are most closely related to the Coelurosauria of the theropod 
dinosaurs finds only low degrees of confidence in the homologues; there- 
fore his group hypothesis has a corresponding low degree of confidence. 
McKitrick (1991) has recently published a most interesting phylogenetic 
analysis of birds using their hindlimb musculature; she presents a phylo- 
geny and compares her conclusions with various recent classifications, 
but she does not present any classificatory hypotheses herself. Close study 
of McKitrick's paper suggests that a serious shortcoming lies in the low 
degree of confidence in the homologies of the several character states 
described for each hindlimb muscle; hence any classificatory hypothesis 
about avian taxa tested against these homologues would have a 
correspondingly low degree of confidence. 

The recently published classification of birds by Sibley & Ahlquist 
(1990), advocating major modifications in the relationships of avian 

W.J. Bock 62 Bull. B.O.C. 11 2A 

orders and families, depends entirely on the degree of confidence that can 
be established for the homology of avian DNA, in as far as Sibley & 
Ahlquist have described and compared it in the diverse taxa of birds. It 
must be emphasized that they have never described the homologies of the 
fragments of DNA subjected to the annealing comparisons used in their 
analysis and have therefore presumably never tested the homology of 
these DNA fragments directly; nor have they provided any estimate of the 
degree of confidence for each conclusion about the fragments of DNA. 
They have merely presumed them to be homologous and have assumed a 
high degree of confidence in all homologies regardless of the extent of 
annealing of DNA from different taxa, even at the lowest percent of 
annealing. Contrary to the claims of Sibley & Ahlquist and some other 
workers, they have not solved the 'problem of homology'. If one con- 
cludes, as I do, that the degree of confidence is low for each (unstated) 
individual test of homology of the many different fragments of DNA 
in the comparisons made by Sibley & Ahlquist, then the degree of 
confidence in their classificatory hypotheses would be correspondingly 
low. The fact that the annealing comparisons involve a large number of 
fragments of the DNA of the taxa compared does not raise the degree of 
confidence, as they claim, in the test of the group hypotheses. The degree 
of confidence in a group hypothesis is not ascertained by a simple addition 
of the degrees of confidence of the individual character hypotheses used 
to test the group hypothesis. Rather the degree of confidence in the 
group hypothesis is largely determined by the degree of confidence in the 
individual character hypotheses. 

e) The method of reciprocal illumination 

A major point made by Hennig (1966: 21) is that "In reality, phylo- 
genetic systematics uses a method known and employed in all sciences, 
which in the humanities is called the 'method of reciprocal illumination' 
(checking, correcting and rechecking of the Anglo-Saxon authors)." 
Hennig suggests that this method involves the formulation of a series 
of character hypotheses, and from this series a group hypothesis is 
generated, which in turn is then used to check further the validity of the 
original character hypotheses which in turn are again used to check 
further the group hypothesis (Hennig 1966: 22). If I understand this 
statement correctly, it is circular in spite of the strenuous protesting 
of Hennig against this conclusion. This method has been cited with 
approval by cladistic systematists and a number of philosophers of bio- 
logy, but without real clarification of the exact procedure employed. 
Either the method of reciprocal illumination as outlined by Hennig is 
circular or the description of the proper working procedure is obscure. 
"Checking, correcting and rechecking" can be interpreted completely 
differently, as an approach which involves the testing of a group 
hypothesis using a series of independently tested character hypothesis, 
thereafter reformulating the group hypothesis depending on the outcome 
of these independent tests, followed by further testing of the modified 
group hypothesis using a series of independently tested character 
hypotheses, including new ones not used in the test of the original group 
hypothesis. Biihler (1980) outlined this approach within the realm of 

Bull. B.O.C. 112A 63 Avian macrosystematics 

N-D E in functional morphology. This is a completely different approach 
from that described by Hennig as I understand it. If this is the approach 
to be used, then the better name would be 'the method of multiple 
independent tests' rather than 'the method of reciprocal illumination'. 


If the above argument on the central role of functional-adaptive analyses 
in macrosystematics is acceptable, then it should be possible to 
demonstrate with case studies that the use of this approach has permitted 
a better understanding of difficult problems in macrosystematics. 

Relationship within the plovers (Charadriidae) 

In a series of papers, P. R. Lowe (see 1922; see also Bock 1958 for 
citations to other papers) discussed the relationship of charadriid genera 
based largely on the ossification of the supraorbital rims of the brain case 
and the colour of the back. He argued that the primitive genera possessed 
less ossified supraorbital rims and a light dorsal colour and that the 
advanced genera had more ossified supraorbital rims and a dark dorsal 
colouration. Although reviews critical of Lowe's papers were published, 
many of his general conclusions formed the basis of the classification of 
this family in Peters' Check-list. Nowhere in his papers did Lowe attempt 
any functional-adaptive analyses; he judged that the less ossified supra- 
orbital rims and lighter colour were primitive ("adumbrated"), claiming 
these were the initial attempt by nature to produce these features, and that 
the more ossified rims and darker colour are the more complete (finished) 
product. In addition, he claimed that the primitive, less ossified supra- 
orbital rims represented the earlier stage in the ontogenetic development 
of these rims, through which the more ossified rims passed earlier in their 
ontogeny. He argued strongly that these features are not directly affected 
by the present-day environment, but represent conditions inherited 
unchanged from the ancestral state. 

In analysing these features in my generic review of the plovers (Bock 
1958), I found the colouration of the dorsum easy to explain. Ever since 
Professor Alfred Newton suggested to H. B. Tristram in 1858 (letter 
dated 24 August 1858— Wollaston 1921: 111-117) that Tristram should 
read the then recently published papers by Darwin and Wallace to explain 
the observed diversity of dorsal colour in African larks, there have been 
numerous papers showing that the dorsal colouration in open country 
birds such as plovers, larks, etc. matches the colour of the substrate 
closely as protective colouration. For Lowe to claim otherwise would 
require extensive supporting evidence which he did not provide. 
Alteration in dorsal colour would occur rapidly in the evolution of 
different species of plovers accompanying changes in the colour of the 
substrate. Moreover, this evolutionary change would readily occur 
independently and would revert equally readily with reverse modification 
of the substrate colour. 

The degree of ossification of the supraorbital rims is almost equally 
easy to explain in terms of functional and adaptive significances. 
Ossification of these rims is inversely correlated with the size of the nasal 

W.J. Bock 64 Bull.B.O.C.UlA 

glands lying in a supraorbital position; larger glands press more on the 
bone, cause its de-ossification and hence reduction in the size of the rims. 
These glands secrete salt and their size is directly correlated with the 
salinity of the environment of diverse species. Evolutionary changes in 
size of the supraorbital rims would track changes in the salinity of the 
environment, would occur independently in diverse species and would 
reverse with increase and decrease in environmental salinity. Indeed 
great changes in the size of the supraorbital rims can be observed in a 
single individual during its life correlated with changes in the salinity of 
its environment. 

Hence it can be shown by rather simple functional-adaptive analyses 
that the different observed states in these 2 characters are either not 
homologous or, if concluded to be homologous in diverse species of 
plovers, they possess a very low degree of confidence, with no possibility 
of establishing which are the primitive and which are the advanced 
characteristics in present-day plovers. Their observed states possess a 
high degree of homoplasy because of their high probability of indepen- 
dent evolutionary origin and reverse evolution. Classificatory hypotheses 
about taxa within the plovers accepted after testing against Lowe's 
characters would have exceedingly low degrees of confidence because of 
the corresponding low degrees of confidence in the character hypotheses. 
In simple words, dorsal colouration and supraorbital rims in the plovers 
are poor taxonomic characters. 

The palaeognathous birds 

The palaeognathous birds comprise the larger flightless ratites and the 
smaller flying tinamous. The question of whether the palaeognathous 
birds or the ratites or both constitute monophyletic taxa has been 
argued by ornithologists ever since these birds were known. Originally 
the flightless ratites were considered to be a monophyletic group, but not 
closely related to the flying tinamous. T. H. Huxley (1867) placed the 
large flightless ratites in the Ratitae, and the tinamous in the Carinatae, 
together with the other carinate birds. Subsequently some workers 
(e.g. Wetmore 1940) placed the tinamous together with the ratites in a 
separate superorder, the Palaeognathae, a monophyletic group within the 
Neornithes. Gradually during this century most ornithologists have 
come to agree that the palaeognathous birds and the ratites are poly- 
phyletic groups. Most avian classifications published after 1940 did not 
recognize the superorder Palaeognathae largely as a result of McDowell's 
conclusions (1948) that the palaeognathous palate is not homologous in 
these birds, but also because of the disjunct distribution of the flightless 
birds. The several families of ratites and tinamous were separated into 
a number of distinct orders which were placed next to one another in 
standard sequences simply because ornithologists had no clues to their 
relationships to other birds. However, a few workers (e.g. Glutz von 
Blotzheim 1958) still argued for the monophyly of the ratites leaving the 
question of the classification of the palaeognathous birds unresolved. 

A resolution of this question was achieved a few years later when Bock 
(1963) showed that a complex suite of cranial characters are all homolo- 
gous in the palaeognathous birds, namely the palaeognathous palate, the 

Bull. B.O.C. 112A 65 Avian macrosystematics 

posterior position of the basipterygoid process and articulation with the 
pterygoid, the large zygomatic process lying along the lateral side of 
the quadrate and closely applied to it, the gap between the maxilla and the 
maxillary process of the nasal, and the continuity of the ossified orbital 
and nasal septa (resulting in rhynchokinesis). Moreover, the degree of 
confidence in these homologues was estimated to be high. All these 
features had been known previously, but a functional-adaptive investi- 
gation permitted the estimation of a high degree of confidence in the 
character hypotheses and hence in the classificatory hypothesis that 
the ratites and tinamous constituted a monophyletic taxon. No other 
classificatory hypotheses were proposed and tested. This classificatory 
hypothesis was supported by other workers, including Meise (1963), 
though he considered only the ratites. 

The question of the interrelationships of the palaeognathous birds 
remained, with considerable diversity of opinions on the placement of 
some taxa within the entire group (Sibley & Ahlquist 1972, 1981, 1990, 
Cracraft 1974, 1981b, 1988, Bledsoe 1988). However, some conclusions 
were widely accepted. The tinamous were considered to be a separate 
taxon and a sister group of the monophyletic ratites. The ostriches and 
rheas were regarded as sister groups, forming a monophyletic taxon 
within the ratites. 

In a subsequent study, Bock & Biihler (1990) tested a series of classifi- 
catory hypotheses, including: whether the Ratitae are a monophyletic 
taxon? (no); whether the Struthionidae and the Rheidae are sister groups? 
(no); whether the Struthionidae and perhaps the Aepyronithidae are a 
monophyletic taxon within the palaeognathous birds? (yes); and, whether 
the Tinamidae, Rheidae, Casuariidae, Dromaiidae, Apterygidae and 
Dinornithidae constitute a monophyletic taxon within the palae- 
ognathous birds? (yes). These hypotheses were tested against character 
hypotheses about the homology of the complex tongue apparatus in these 
birds. A number of skeletomuscular attributes of the tongue apparatus 
present in the ostriches are not homologous with those present in the 
other palaeognathous birds. Moreover, it could be argued that the 2 
different configurations of the tongue apparatus present in the palaeog- 
nathous birds could not have evolved from each other, but rather each 
type of reduced tongue evolved independently from a well-developed 
tongue in the immediate common ancestor of the 2 monophyletic taxa 
within the palaeognathous birds. The character hypotheses possess high 
degrees of confidence, and hence the group hypotheses tested against 
them also possess high degrees of confidence. 

Bock & Biihler's classificatory hypotheses differed in several important 
aspects from previous conclusions. They concluded that the Ratites are 
not monophyletic within a monophyletic Palaeognathae, and that the 
Tinamidae is not the sister group of all ratites, but of the Rheidae. 
These conclusions are radically different from those presented by Sibley 
& Ahlquist (1981, 1990) based on DNA studies. Assessment of which of 
these disparate conclusions, if either, are correct depends largely on an 
evaluation of the degrees of confidence in exact character homologues, 
particularly of those DNA fragments used by Sibley & Ahlquist to test 
their several conclusions about palaeognathous birds. 

W.J. Bock 66 Bull.B.O.C. 11 2A 

Neotropical flowerpiercers 

A small group of 10-17 species of Neotropical nectar-feeding birds 
found in the mountainous forests from Mexico to Argentina, commonly 
called flowerpiercers because of their method of cutting into the corolla of 
flowers to obtain nectar, had been placed in a monotypic genus Diglossa 
ever since their discovery until Bock's (1985a) classificatory hypotheses 
that the flowerpiercers are members of 2 genera, Diglossa and Diglossopis, 
and that these genera are not closely related to one another within the New 
World 9 primaried oscines, e.g., the Thraupinae. The hypotheses were 
tested against a series of character hypotheses about the homology of 
features in the skull, the corneous tongue and the rhamphotheca of these 
species. The conclusions that these features are not homologous in the 2 
groups of species permitted acceptance of the classificatory hypotheses. 
A brief functional-adaptive analysis of the corneous tongue, which serves 
to obtain nectar, was critical to this decision and the accompanying con- 
clusion that the 2 genera evolved flower-piercing habits and associated 
specializations independently. 

The passerine finches 

The classification of Old World finches has been a major problem for 
systematists from the beginnings of avian classification. During this 
century the passerine finches {Passer and its relatives) have usually been 
placed in the Ploceidae, sometimes in a separate subfamily as in Peters' 
Check-list. The discovery (Bock & Morony 1978a) of a unique neo- 
morphic bone, the preglossale, in the tongue of these birds permitted 
the testing of the classificatory hypotheses that the genera Passer, 
Montifringilla and Petronia constitute a monophyletic assemblage and 
that this group is not part of the Ploceidae (Bock & Morony 1 978b). These 
group hypotheses were supported by the homology of the preglossale, the 
presence (homology) of the M. hypoglossus anterior, and the homology of 
the 'seed-cup' in these genera. Functional analyses of the thick corneous 
tongue in seed-eating passerine birds as a seed-cup used to manipulate 
seeds during their shelling and an understanding of the evolution of 
muscles and bones in vertebrates gave the character and corresponding 
group hypotheses high degrees of confidence. This was contrary to the 
conclusions of Sibley & Ahlquist (1985: 144), which, however, they later 
(1990: 675-683) changed to agree with Bock & Morony without comment 
on their earlier conclusions. Although the affinities of the passerine 
finches to other oscine birds is still unresolved, their membership in the 
Ploceidae and the Estrildidae can be ruled out. 

The South African sugar bird 

The curious genus Promerops, or Sugar Bird, from South Africa has 
defied avian systematists in their attempts to place it within the system of 
oscine birds. It has usually been placed in a monotypic family or in the 
Australasian family Meliphagidae; the latter placement is puzzling 
because of the great ocean gap between South Africa and the range of the 
rest of the Meliphagidae. Sibley & Ahlquist (1985: 144, 1990: 670-675) 
concluded on the basis of DNA annealing that Promerops is a member 
of the Nectariniidae. Bock (1985b) tested the dual hypotheses that 
Promerops is a member of the Nectariniidae and that Promerops is a 

Bull. B.O.C. 112A 67 Avian macrosystematics 

member of the Meliphagidae against character hypotheses on homologies 
of the skull and tongue apparatus. These tests do not support the 
hypothesis that Promerops is a member of the Nectariniidae. Especially 
important is the non-homology of the thick-walled, quadrifid, fringed, 
tubular tongue in Promerops and the thin-walled double-tubed corneous 
tongue with few broad, flag-like laciniae in the nectariniids. If Promerops 
is a nectariniid, then the common ancestor of Promerops and other 
nectariniids was not specialized to feed on nectar. Homologies in skull 
structure and corneous tongue of Promerops and of the meliphagids 
support the hypothesis that Promerops is a member of the Meliphagidae, 
but they do not possess high degrees of confidence. Although it is not 
possible at present to distinguish Promerops from the Meliphagidae, it is 
still possible that the South African Sugar Bird evolved from some other 
oscine family; but strong arguments can be raised against placement of 
Promerops in the Nectariniidae. It should be noted that Sibley & 
Ahlquist's argument that Promerops is closely related to the New Guinean 
genera Toxorhamphus and Oedistoma, and that these 2 latter genera are 
nectariniids must be examined carefully because these 2 genera share 
many homologous features of the tongue apparatus with those of the 
meliphagids and few, if any, with those of the nectariniids. 

The piciformes 

The monophyly of the Piciformes has been the subject of considerable 
dispute for the past decade, involving the question whether the 
families Galbulidae and Bucconidae (jacamars and puffbirds), which are 
often placed in a distinct suborder- — the Galbulae, are members of the 
Piciformes. All major classifications of birds include the Galbulae in the 
Piciformes in spite of the thorough analysis of G. Steinbacher (1935), 
who showed that details of the distal tarsometatarsal condyles and other 
features associated with the reversed fourth toe in the zygodactyl foot 
of the Galbulae are strikingly different from those present in the Pici. 
Unfortunately, he never discussed the significance of his findings for the 
macrosystematics of the piciform birds. Although Steinbacher (1935: 
277) spoke of 4 different 'bauplans' of zygodactyl feet in birds, this 
expression is uninformative about their evolution. J. Steinbacher (1937) 
undertook further investigations of the Galbulae and concluded that they 
were properly placed in the Piciformes; he did not discuss the findings of 
G. Steinbacher. It is interesting that Stresemann (1959), who recognized 
many of Wetmore's suborders as distinct orders, retained the Galbulae in 
the Piciformes. In companion papers, Swierczewski & Raikow (1981) and 
Simpson & Cracraft (1981) analyzed the classification of the Piciformes 
and concluded that this order was monophyletic. Olson (1983) disagreed 
and concluded that it was polyphyletic and that the Galbulidae and 
Bucconidae are related to the Coracii (Coraciidae and their allies). Raikow 
& Cracraft (1983) countered Olson's conclusion. I would like to concen- 
trate on the first part of Olson's conclusion, namely the polyphyletic 
nature of the Piciformes. 

Olson is quite correct in calling attention to the different con- 
figurations of the zygodactyl foot in the Galbulae and Pici. Character 
hypotheses can be formulated as to whether the structural details of the 

W.J. Bock 68 Bull. B.O.C. 1 12A 

distal tarsometatarsal condyles and associated ligaments of the zygodactyl 
foot of the Galbulae are homologous with those of the Pici as attributes 
of a zygodactyl foot. Testing these hypotheses against empirical obser- 
vations of foot structure in these 2 forms of birds, results in rejection of 
the hypotheses. [It should be noted that contrary to the implication given 
by Olson ( 1 983 : 1 27), the earlier analysis of Bock & Miller (1959) was not 
concerned with the question of whether or not the several different types 
of zygodactyl feet as seen in cuckoos, parrots, galbulids and picids evolved 
independently; hence the earlier findings of G. Steinbacher were ir- 
relevant to their analysis.] The functional-adaptive analysis presented by 
G. Steinbacher (1935) and later discussions of Bock & Miller (1959) can 
be used to argue that the non-homology of the zygodactyl foot in galbulids 
and picids has a high degree of confidence. The counter arguments pre- 
sented by Raikow & Cracraft (1983) simply do not touch on the major 
points raised by Olson. Moreover, Raikow & Cracraft (1983: 134) commit 
a major error in stating that "We suggest that the zygodactyl conditions 
of the Galbulae and Pici are homologous because other characters (see 
below) corroborate the unity of the Piciformes." Testing and acceptance 
of a hypothesis on the homology of one feature cannot be based on a 
presumed affinity of the organisms possessing this feature or on a 
correlation with other presumed homologous features. By making this 
statement, Raikow & Cracraft remove the zygodactyl foot from any 
further use in testing group hypotheses about the Piciformes — a 
procedure which should be avoided in macrosystematics. 

The South American hoatzin 

Perhaps of all problems facing avian macrosystematics, the affinities of 
the hoatzin, Opisthocomus, is the most vexing. It was originally described 
in the genus Phasianus in 1776 and only placed in the monotypic genus 
Opisthocomus in 1811. Over the years this bird has generally been placed 
in the Galliformes or the Cuculiformes, or in a group (a separate order) 
intermediate between the two, but for the past century most workers 
have included the hoatzin in the Galliformes as a separate suborder. 
More recently Sibley & Ahlquist (1973, 1990) have concluded that 
Opisthocomus is a member of the Cuculiformes and is most closely allied 
to genera such as Guira and Crotophaga, originally on the basis of a 
comparison of egg-white proteins and later of DNA annealing. In their 
extensive discussion of the history of systematic analyses and character- 
istics of Opisthocomus, Sibley & Ahlquist fail to mention an important 
attribute of this bird (Bock, in press) — namely that the arrangement of the 
toes in the hoatzin is anisodactyl, not zygodactyl as in all members of the 
Cuculiformes. Examination of skeletons of Opisthocomus shows that this 
bird lacks completely the specializations described by G. Steinbacher 
(1935) for the cuckoo tarsometatarsus which are associated with their 
zygodactyl foot, permitting reversal of tendons to the fourth toe. The 
zygodactyl foot of cuckoos is an adaptation for perching and is so used in 
most forms of cuckoos, including those genera concluded by Sibley & 
Ahlquist to be the closest relatives of the hoatzin. Hoatzins are specialized 
for life in trees, and if they descended from cuckoos, there is no way that 
the hoatzin anisodactyl toe arrangement would have evolved from the 

Bull. B.O.C. 112A 69 Avian macrosystematics 

cuckoo zygodactyl arrangement under selective demands for these habits 
(Bock & Miller 1959). Hence there is no way to support the conclusion 
that the hoatzin evolved from an ancestor with a zygodactyl foot such 
as possessed by cuckoos. Sibley & Ahlquist did not conclude that 
Opisthocomus was a sister group of the cuckoos, but that it evolved from an 
ancestor in the middle of the cuckoo radiation and therefore from an 
ancestor possessing a zygodactyl foot. Therefore testing the classificatory 
hypothesis that Opisthocomus is a member of the Cuculiformes against 
character hypotheses about the homology of toe arrangement would 
result in its rejection with a high degree of confidence because the 
arrangements of the toes in the Cuculiformes and in Opisthocomus are 
not homologous with any degree of confidence. At the present time, the 
position of Opisthocomus in the system of birds is uncertain, but it is not a 
cuckoo. Possibly it is a remnant of an old South American radiation most 
of which has become extinct; if so, the relationships of the hoatzin to other 
birds could be difficult to ascertain. 


The theoretical discussion and the several case studies presented above 
demonstrate that a convincing classification of birds is almost completely 
dependent on thorough and proper analyses of character hypotheses, 
including the demonstration of high degrees of confidence in the taxo- 
nomic properties of characters used to test classificatory hypotheses 
about groups. Functional-adaptive investigations are the critical part 
of character analysis, both in the empirical testing of the character 
hypotheses and in the determination of their degrees of confidence. 
Therefore until avian systematists give careful attention to functional- 
adaptive investigations in the analysis of the taxonomic properties of 
characters, no convincing progress will be made in avian macro- 
systematics regardless of the efforts made in the search for new taxonomic 
features or in the development of computer methods for analyzing large 
numbers of characters to formulate the most 'parsimonious' classifi- 
cations. After nearly 150 years since publication of 'On the Origin of 
Species', the time has come to insist that macrosystematic methodology be 
formulated on evolutionary theory. 


I would like to thank Dr. J. F. Monk for inviting me to contribute a paper to the Bulletin of 
the B.O.C. Centenary Supplement and for his excellent assistance in editing the paper, 
which is much improved through his efforts. 


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© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 11 2A 73 PA. Clancey 

Subspeciation, clines and contact zones in the 
southern Afrotropical avifauna 

by P. A. Clancey 

Received 19 February 1991 

The following appraisal of current understanding of the complex patterns 
of variation in resident birds in southern Africa and their interpretation 
in the recognition of sub- and allospecies, clines and contact zones is 
presented in order to foster continued research in this vital field of 


It has been said that subspecies in birds are a matter of opinion, species a 
matter of fact and genera a matter of convenience. Like all such trite 
comments, the views expressed are only true in part, but, nevertheless, 
they correspond with those held by many non-systematists. With effec- 
tive research, given the requisite material and time to investigate the 
issues in depth, a conclusion on the desirability of subspecific recognition 
can assuredly be a statement of fact. The subspecies, albeit sometimes 
used with a measure of diffidence, will maintain its vital status as the 
lowest taxonomic category recognised in nomenclatural terms by the 
International Commission's Code of Zoological Nomenclature. It fulfils an 
integral role in the naming of discrete populations and complexes of 
distinguishable forms of polytypic species, enabling circumvention of 
most of the contentious issues encountered by earlier workers who pinned 
their faith in the maintenance of rigid binomialism. That vertebrates (and 
others organisms) varied geographically was indeed appreciated by many 
early taxonomists, who were disposed to rank such variants as full 
species. Formulation of the subspecies concept dates from about the time 
of C. W. L. Gloger (1803—1863) and the contemporary publications on 
evolutionary theory by Charles Darwin. 

The effective study of subspeciation in species with largely continuous 
continental ranges demands ready access to an extensive volume of 
material, generally far in excess of that held by the largest of museums. 
In Africa such research is handicapped by the distant siting of basic 
collections of the continent's birds in European and North American 
centres, making access difficult and expensive, while in the case of the 
vital East African sector, virtually all the well-prepared collections 
formed since the 1939-1945 war are remotely housed in the United 
States. Conversely, the copious South African and Zimbabwean material 
brought together since the early 1 950s is available in the Southern African 
Subregion's major museums, and has figured extensively in the research 
on the avifauna of the south-central, eastern and southern Afrotropics by 
local ornithologists. In the following discussion I draw freely on data 
from this research carried out in the south of the continent and to be 
found in journals of mainly African museums and ornithological societies 
published between 1950 and 1991. 

P. A. Clancey 74 Bull. B.O.C. 1 12A 

Map 1 . The Afrotropical Region showing the distribution of the South West Arid Zone 
(shaded) and adjacent environments. 1 = savanna woodlands (mainly Miombo); 2 = mixed 
forest bushveld and grassland-types; 3 = Cape Fynbos (macchia) and temperate forest. 

Variation in the South West Arid Zone 

The geographical variation patterns displayed by birds — their races 
or subspecies — in south-central and southern Africa are in the main 
prescribed by the disposition of the major plant communities of the South 
West Arid Zone, which covers rather more than 50% of the Afrotropics 
south of 16° S. Also influential in this regard are the woodlands of the 
so-called Miombo savanna juxtaposed to the north and northeast of the 
said zone, south to the arid valley of the Limpopo R., where the savanna 
type terminates, these playing a like but rather more restrictive role in the 
determination of racial range patterns. To the south of these dominant 
biotic sectors, a mosaic of veld-types, ranging from upland to even 
alpine grassland, bushveld and, to a limited extent, evergreen forest, 
both coastal and montane, exert a not indecisive influence in the marked 
subspeciation of many plastic species. 

In a recent study into endemicity levels in birds of regions south of 
16° S in Africa, but mainly in the South West Arid Zone, c. 70% of the 
some 1 70 regional endemics were found to be peculiar to desertic country, 
a finding supporting the view that this xeric avifauna had remained 
largely unaffected by the climatic and biome oscillations of the 
Pleistocene and immediate subsequent times. In contrast, the eastern 
and southern veld-types present to the south of the Miombo savanna 
woodlands (which support an interesting range of endemics) are poorly 
endowed with species peculiar to them, this being the outcome un- 
doubtedly of the ecological history of such habitats stemming from the 
disturbing expansions and contractions of the Lower Guinea Forest. 
Such major disruptions affected savanna bird species in particular, 
leaving to this day their indelible imprint stratified west to east and in the 
ripple-like configuration revealed in the range-maps of many species and 

Bull. B.O.C. 1 12A 75 Subspeciation in southern Afrotropics 

species-groups. In such situations, the remnant form derived from the 
primal colonization — now at the level of a discrete species — is confined to 
a narrow range in the southwestern corner of Africa, with the descendants 
of later expansionary thrusts lying stratified and at differing stages of 
evolutionary development disposed to its north and northeast. That the 
ranges of the individual forms are not infrequently wholly or partially 
interlarded by untenanted tracts of country is of no small biogeographical 
significance. This is lucidly demonstrated in the barred bush warblers of 
the genera Calamonastes and Euryptila (Clancey 1986,esp. Fig. 3, p. 258). 

The broad pattern of savanna species distribution reveals a pronounced 
continental bias from the northeast to the south in species recruitment, 
and surprisingly little in the reverse direction. That such southward 
oriented augmentation is not a thing of the past is clearly illustrated in the 
increasing occurrence of the Golden Pipit Timetothylacus tenellus — an 
endemic characteristic of the North Eastern Arid Zone — in the north- 
east of southern Africa from Zimbabwe to the plateau of the Transvaal. 
Analogous situations exist in some species which extend far beyond the 
Afrotropics, as instanced by the Long-billed Pipit Anthus similis, which 
extends from the desertic south of the central Palaearctic and north- 
western Indomalaya to the northeastern and southwestern drier country 
of the Afrotropics. These 2 Afrotropical population groups are separated 
from one another by intrusive elements of the confusingly similar Wood 
Pipit Anthus nyassae, a pipit of the Miombo biome of south-central Africa 
and discrete from similis in both morphology and ecology, which derives 
from a like but earlier lineage to that of the contemporary A. similis (see 
especially Clancey 1985). The occurrence of similis in the southern parts 
of Africa was seemingly accomplished by leap-frog colonization across 
unsuitable country and the savanna woodlands inhabited by nyassae 

The broad spectrum of the Palaearctic/Afrotropical bird migration 
system also furnishes instructive similarities, especially so in the cases of 
northern species which, through the millenia, have founded colonies in 
Africa, again in the east and south of the continent. Noteworthily, 
these again are birds of largely open country environments, particularly 
savanna types, and not of heavy forest. These colonizations tend to under- 
score the overriding ecological impact which the seasonal unsuitability of 
the northernmost sector of the Eurasian landmass has for long exerted in 
the development of survival strategies in many birds; whereas compar- 
able conditions in the southern hemisphere are only to be found to a 
limited extent in the south of South America and still less so in southern 

The broad patterns of geographical variation in southern African birds 
and their taxonomic interpretation are closely correlated with major 
vegetational facies and precipitation gradients, conforming closely with 
those found elsewhere in the world where habitats range sequentially 
from hygric forest, moist and dry savanna to near absolute desert. In 
species characteristic of the South West Arid ecosystem, mensural vari- 
ation is circumscribed in inhabitants of savanna woodland-types, but is 
pronounced in terrestrial feeders such as larks, in which the length and 
mass of the bill may visibly increase in clear reaction to the hardness of the 

P.A.Clancey 76 Bull. B.O.C. 11 2A 

substrate. For example, there is a marked increase in the bill-mass in 2 
karooid races of the Sabota Lark Mirafra sabota (M.s. bradfieldi and 
herero) compared with its other subspecies, of which there are 8, and 
which are relatively slender billed by comparison. Substrate-related 
variation in bill-form also occurs in forms of Certhilauda spp., especially 
in the Long-billed Lark C. curvirostris and the isolated Red Lark C. 
( erythrochlamys ) burra, which hybridizes on its periphery with the more 
slender-billed Karoo Lark C. albescens. Just to complicate matters, there 
is a marked difference in bill-length and profile between the sexes in 
certain of the Certhilauda taxa, yet, interestingly enough, such plasticity 
in bill-facies is not evident in nearly all other sympatric alaudids. 

The plumage of larks, perhaps more so than other terrestrial birds, also 
varies with local shifts in ground-colour as well as texture (as clearly 
shown by Hoesch & Niethammer 1940), yet their overall variation pat- 
terns are concordant in many respects with those of polytypic species not 
overtly affected by edaphic factors, such as the equally terrestrial pipits 
{Anthus spp.). Response to local changes in soil-colour reaches its 
extreme in the mosaic of subspecific forms in the Spike-heeled Lark 
Chersomanes albofasciata, which highly variable species is centred on 
the arid zone, but which extends in to country to the southeast and north 
of its core, and has even founded a distant isolate population in northern 
Tanzania. Despite the high measure of purely localized response to soil- 
colour change, the overall pattern in C. albofasciata is in line with the 
norm, in that the more deeply coloured races are found in the mesic 
south and southeast and the palest along the xeric edge of the Namib in 
northwestern Namibia. The change from dark to light is a progressional 
or clinally stepped mosaic-cum-gradient. Fourteen subspecies of C. 
albofasciata are admitted in the 1980 S.A.O.S. Checklist for the Southern 
African Subregion alone, while yet others have been proposed. 

In moderately polytypic species other than larks centred on the arid 
zone, relevant taxonomic variation is generally accommodated by the 
formal recognition of 4 or more subspecies on characters analogous to 
those just outlined for austral African larks. In considering other in- 
stances of edaphic and phenotypic reaction, the status of both localized 
and widely fragmented populations breeding on the glaring substrate 
of saline pans in the interior of northern Namibia and the Kalahari 
region of Botswana, northeast to northwestern Zimbabwe requires to 
be mentioned, since more than just larks are affected. These interior 
localized saline pans are tenanted, often seasonally, by very pallid forms 
of francolin (Francolinus levaillantoides subspp.), sandplovers Charadrius 
spp., coursers Cursorius & Rhinoptilus spp., sandgrouse Pterocles spp., 
small nomadic larks of the genera Calandrella, Spizocorys and 
Eremopterix, and pipits Anthus spp. Environmental glare and not soil- 
colour is seen as the deciding factor in determining the colouration of such 
salt-pan forms. 

Variation in the mesic sectors 

In the wide range of moister habitats arcing round the arid sector on 3 
sides, conditions for extensive subspeciation among savanna breeders 

Bull. B. O.C. 112A 77 Subspeciation in southern Afrotropics 

exist, yet, significantly enough, these same habitats carry many fewer 
endemics. This is an outcome of the dynamics of the biota's Quaternary 
past. Study of some of the relicts reveals they have responded to the 
interplay of local ecological factors, for example in both the localized 
Ground Woodpecker Geocolaptes olivaceus and the Knysna Woodpecker 
Campethera notata. G. olivaceus is an aberrant eurytopic picid of both 
Karoo and Afro-montane grassland types, and at some stage in its evolu- 
tionary history its range was split and polarized in western and in eastern 
refugia, the 2 populations later meeting in a zone of secondary contact in 
the eastern Cape Province (see Clancey 1988). Recent study has con- 
firmed that 3 races are admissible and that an earlier recommendation that 
the variation was clinal and the species monotypic was unjustified (pace 
Earle 1986). Regional variation in the forestal C. notata pursues a differ- 
ent course, its disposition and morphology being dictated by the nature of 
its woodland niche, with one race centred on stands of Euphorbia and dry 
bushveld and the other on coastal evergreen rain-forest and its remnants. 
Its phylogenetic status is somewhat clearer than that of G. olivaceus, as 
its general colour saturation, green colouration and heavy black ventral 
spotting connote a relationship with contemporary equatorial forest 

In some complexes of what may be termed residual relicts, i.e. relict 
species without verifiable extinct or surviving relatives, the ancient 
splitting of the deep southern Afrotropical avifauna into 2 small refugial 
areas at one stage furnished the isolating mechanism basic to the develop- 
ment of allospecific pairs in the region, as in the sugarbirds Promerops 
cafer and P. gurneyi, the rockjumpers Chaetops frenatus and Ch. aurantius 
and in the siskins Pseudochloroptila totta and Ps. symonsi. These allo- 
specific pairs are narrowly distributed west to east in association with 
the main mountain ranges from the western Cape to the Drakensberg 
complex in the east, though in each instance the individual species of the 
pairs are spatially segregated in the critical eastern Cape region (the 
putative site of the ancient refugial rift). In the case of P. gurneyi, a major 
range extension must have occurred at some stage to found the population 
present in the eastern Zimbabwe frontier mountains (P.g. ardens), and 
similarly in the endemic bush shrike Telophorus zeylonus. 

A singularly important faunal area is that of the ecotone which 
separates the Julbernardiaj Brachystegia woodland savanna (Miombo) 
of south-central Africa from the Acacia and associated dry-country 
vegetation to its south, and which is distributed from southern Angola 
and northern Namibia eastwards. Here the geographical variation in 
many birds is in the form of a marked increase in overall size together with 
the assumption of greyer colouration over the upper-parts, and in some 
there is a decided thickening of the bill, for example in the race of Red- 
eyed Dove Streptopelia semitorquata maxima and that of the Thick-billed 
Weaver Amblyospiza albifrons maxima; the latter, significantly, parallels 
a comparable increase in bill-mass in the races of the Yellow-rumped 
Bishop Euplectes capensis in the Cape's Winter Rainfall District. The 
ecological basis of the increase in size and colour modification in such 
residents of the southern Angola/northern Namibia ecotone is currently 

P. A. Clancey 78 Bull. B.O.C. 1 12A 

The avifauna of the mid-Kunene R. to the west of the ecotone has its 
composition effectively modified by the ambient aridity of the rivercourse 
as it transects the Namib. On the other hand, the Okavango R. to the east, 
which flows through the same ecotone, supports an essentially riverine 
avifauna, which is disparate yet richer in its species composition. This 
results from the river's flanking vegetation permitting several forms from 
the hygric parts of central and northern Angola to penetrate the northeast 
of the South West Arid Zone. Nevertheless, the vegetation of the mid- 
Kunene also facilitates some southward range extension in species with 
equatorial but rather more western affinities. For example, the Kunene 
race of S. semitorquata is the nominate, with S.s. maxima (see above) 
replacing it along the Okavango (Clancey 1986a, 1989b); in the Green 
Pigeon Treron calva, T.c. ansorgei is replaced by T.c. damarensis along the 
mid-Okavango. This same pattern is evident in a wide range of other 
polytypic species, including the woodhoopoes Phoeniculus damarensis (in 
the west) and P. purpureus angolensis (in the east), and the Long-tailed 
Glossy Starling Lamprotornis mevesii with L.m. violacior and L.m. 
benguellensis in the west and nominate in the east (Clancey 1973). Of 
moment from the ecological standpoint is the parallel bronzing in the 
plumages of P. damarensis and L.m. benguellensis, which are sympatric in 
the southwest of Angola. 

Over the plateau of Zimbabwe and adjacent Mozambique, thence 
extending on to the littoral plain, is the southeastern terminal block of 
the Miombo savanna, which is effectively sundered from the main stand 
lying to the north by the dry Zambezi and Luangwa valleys. This partial 
isolation is reflected in the presence of a range of Zimbabwean races of 
species either endemic to or closely associated with the plateau sector of 
the Miombo savanna. However, in the eastern lowlands the influence of 
any rivercourse sundering of the environment is minor, as the woodlands 
are continuous, and, strangely enough, the wide lower reaches of the 
Zambezi and its flood-plain in Mozambique do not form a functional 
faunal barrier; more or less continuous populations of a species present 
both to the north and south of the Zambezi frequently do not differ at all 
racially. Such influence as the west/east faunal divide of the Rift exerts in 
the distribution of taxa at this latitude in the Afrotropics also appears 
circumscribed, except in cases such as the turaco (lourie) forms Tauraco 
livingstonii and T.(l.) schalowi, and, again, in the savanna barbets 
Stactolaema whytiijsowerbyi, which may or may not be conspecific, as 
frequently treated. 

It has not been generally appreciated by those interested in zoogeo- 
graphy that the most effective river faunal divide in the southeast of Africa 
is that furnished by the mid- and lower Limpopo R., reinforced as it is by 
the eastward extension of the arid climate of the desertic western and 
interior landmass of the southern parts of the continent. This last is 
convincingly shown by the finding of discrete races in the east of Sul do 
Save, southern Mozambique, of such dry country inhabitants as the small 
granivores: the Shaft-tailed Whydah Vidua regia and the Violet-eared 
Waxbill Uraeginthus granatinus. 

The localized Miombo subspecies present on the Zimbabwe plateau 
are in the main restricted distributionally, while those of the same biome 

Bull.B.O.C. 112A 

79 Subspeciation in southern Afrotropics 



East London 

Port Elizabeth 

Map 2. The eastern aspects of the Southern African Subregion showing major geographical 
features alluded to in the general discussion. 










Rift of Malawi (and Shire R. valley) 

Lower Zambezi R. 

Mid-Zambezi R. valley 

Zimbabwe/Mozambique frontier highlands 

Save R. (Sabi R. in Zimbabwe) 

Limpopo R. (and terminal limit of the Miombo savanna) 

Upper Limpopo R. valley 

Transvaal Drakensberg Mtns 

Lake St Lucia region 

Drakensberg massif 

Great Fish R. 

Okavango R. 

Okavango R. delta and swamp 

in the eastern lowlands normally range well to the north of the Zambezi, 
as in such forms as the Mashona Hyliota Hyliota australis inornata, the 
Red-faced Crombec Sylvietta w. whytii, and the Mozambique Batis Batis 
soror. The Save R., interposed in Mozambique between the Zambezi and 
Limpopo, forms the contact zone between complexes of some polytypic 
species; among those which may be mentioned are the boubous Laniarius 
ferrugineus and L. aethiopicus, and the camaropteras (bleating bush 
warblers) Camaroptera brachyura and C. brevicaudata (which hybridize 

P. A. Clancey 80 Bull. B.O.C. 1 12A 

narrowly in the Zimbabwe/Mozambique frontier highlands to the west- 
Clancey 1970), while genes of brevicaudata introgress deeply through 
the littoral race of the Green-backed Camaroptera C. brachyura (C.b. 
constans) to terminate in the northeast of Zululand. The Save valley 
likewise plays a similar dispositional function in the Black-collared 
Barbet Lybius torquatus, with L.t. lucidiventris present to the south of the 
river and L.t. vivacens to the north, the 2 races being part of sequential 
change from scarlet on the head in the south to creamy or pinkish white to 
the east of L. Malawi, only to revert to bright scarlet again in East Africa 
in L.t. irroratus. It may also be mentioned here that the 2 minor forms of 
Woodwards' Batis Batisfratrum also merge in the Save R. area. 

As alluded to earlier, endemics peculiar to the mesic east of southern 
Africa are relatively few in number. In Zimbabwe only 2 occur. The 
Boulder Chat Pinarornis plumosus, best considered as an integral element 
of the Miombo avifauna, though confined to rock outcrops and boulder 
accumulations in the savanna, has a population enclave across the 
Zambezi in southeastern Zambia and adjacent territories, but no estab- 
lished extant relatives. The second Zimbabwean endemic (and relict) is 
the so-called Roberts' Prinia Oreophilais robertsi of the frontier highlands 
between Zimbabwe and Mozambique. This is yet another species with- 
out established extant allies, which has recently been categorized as 
belonging to a new monotypic genus (Clancey 1991), having a tail of only 
8 rectrices as opposed to the 10 in other long-tailed warblers grouped in 
the genus Prinia Horsfield. 

Littoral endemics of the southeast of the Afrotropics south of the 
Zambezi are Neergaard's Sunbird Nectarinia neergaardi, Rudd's Apalis 
Apalis ruddi, the Lemon-breasted Canary Serinus citrinipectus and the 
Pink-throated Twinspot Hypargos margaritatus, currently under threat 
of extinction from the continuing expansion of its close relative H. 
niveoguttatus (see Clancey 1986). 

Variation in southeastern humid lowland forms is manifest in increased 
saturation and lipid levels and a reduction in size, in line with both 
Gloger's and Bergmann's rules, compared with conspecific races occur- 
ing over the interior plateau. Diminution in size not only affects wing- and 
tail-lengths, but also the mass of the bill in some species, as in 2 small 
hornbills — the Southern Yellow-billed Tockus leucomelas parvior and the 
Red-billed T. erythrorhynchus degens. 

The region immediately to the south of the Limpopo R. is, in the east, 
dominated by the Drakensberg montane system and its complex mosaic 
of grasslands, intrusive bushveld and patches of evergreen forest, the 
avifaunal composition of which, as previously asserted, bears the imprint 
of the major climatic and vegetational vicissitudes of the Quaternary. 

Apart from the actual composition of the bird-fauna are the large 
breaks in the ranges of some widely distributed species, the gaps consist- 
ing of stretches of what, to human eyes, is eminently suitable terrain lying 
untenanted. The reason for this is obscure, but presumably some ancient 
disruption in the pattern of colonization, or the dying out of populations 
through competition or local disease may have precipitated it. Such range 
disruptions are found in the Olive Woodpecker Mesopicos griseocephalus 
and the Plainbacked Pipit Anthus leucophrys, and in a rather different 

Bull. B.O.C. 1 1 2A 81 Subspeciation in southern Afrotropics 

version in the 2 white-browed subspecies of the Fiscal Shrike, Lanius 
collaris subcoronatus and L.c. aridicolus, of the Southern African 
Subregion and the isolate L.c. marwitzi of southern Tanzania. 

The Drakensberg region is the redoubt of a number of small grassland 
endemics, such as Rudd's Lark Heteromirafra ruddi, Botha's Lark 
Spizocorys fringillaris, and 3 or so pipits. Of the latter, the most 
noteworthy is the Mountain Pipit Antnus hoeschi, initially described by 
Professor Erwin Stresemann in 1938 from the Erongo Mtns of Namibia, 
where the type-material was taken while the birds were on migration. 
A. hoeschi breeds in the higher and alpine grasslands of the massif of the 
Drakensberg, spending the non-breeding season in the Zambezi/Zaire 
watershed. Rudd's Lark and another of the pipits — the Yellow-breasted 
Hemimacronyx chloris — have spatially remote congenerics in East and 
northeastern Africa. The Drakensberg area also boasts of a range of en- 
demic turdines, such as the Buff-streaked Chat C ampicoloides bifasciatus, 
which has no extant relatives (Clancey 1990), and 2 rockthrushes 
Monticola spp., deriving from old colonisations by Palaearctic ancestors. 
Among non-passerine endemics, also relevant are the Bald Ibis 
Geronticus calvus and the small bustards Eupodotis caerulescens and E. 

Of biogeographical import is the limited range of endemics confined to 
stands of evergreen forest present locally over the southeastern highlands 
and southern mountains (see Clancey 1986), notable among which are 
the Southern Mountain Buzzard Buteo trizonatus, the Knysna Lourie 
Tauraco corythaix and the Bush Blackcap Lioptilus nigricapillus, 
amongst others. Regarding subspeciation, it is worthy of note that in 
some characteristic forestal species, southern populations have diversi- 
fied from restriction to a forest environment and now exploit niches in 
both mesic and xeric habitats, this translating into the development of dry 
country subspecies. Such birds are the Olive Thrush Turdus olivaceus 
(with the xeric T.o. smithi nearing the level of a full species), the Cape 
Robin Cossypha cqffra and the small Lesser Double-collared Sunbird 
Nectarinia chalybea, the extralimital parts of their ranges being tenuous 
and fragmented compared with what is found in the south of the conti- 
nent. In the sunbird, close analogues in the sub-genus Cinnyris replace it 
to the north of the Limpopo R. (Clancey & Irwin 1978, Clancey 1986). 

What may be referred to as the terminal avifaunal division of the 
Afrotropics, namely the Winter Rainfall District of the Cape, supports a 
limited number of endemics restricted to the Cape Fynbos (Macchia) 
biome, dominated by Protea and heath Erica spp. Among these are the 
Cape Sugarbird Promerops cafer referred to earlier, Victorin's Scrub 
Warbler Bradypterus victorini, the Orange-breasted Sunbird Nectarinia 
violacea, the Protea Seed-eater Poliospiza leucoptera and the Cape Siskin 
Pseudochloroptila totta. The entire region is relatively constricted, 
being centred on the mountains (and then largely on their seaward facing 
versants) lying to the south of the South West Arid Zone from the Cape of 
Good Hope, eastwards to just west of Algoa Bay. Taxonomically relevant 
variation in local polytypic bird species differs little from that defined 
above for those present in the east of southern Africa, but on the whole 
shows an inclination towards a still more saturated and heavily marked 

P. A. Clancey 82 Bull. B.O.C. 1 12A 

dorsal and ventral plumage. Variation in size is limited, but, as shown 
earlier, can affect bill-mass, as in the bishop Euplectes capensis. 


The cline concept as initially proposed by J. S. Huxley (1939) has 
frequently been misapplied in avian systematics, consistently so by 
some authors who have found its use advantageous in the disposing of 
otherwise intractable problems encountered in research into geographical 

In the southern third of Africa variation interpretable as clinal sens, 
strict., is to be found in remarkably few birds. Those so affected are largely 
centred on arid country, the biota of which, as demonstrated earlier, was 
much less affected by the disruptive events of the Quaternary. In the case 
of the mesic north and in the east and south, clinal variation has not been 
found in the many (polytypic) species closely studied in recent years, 
this finding being a result of the periodically disrupted pattern of faunal 
augmentation which characterizes the regions' immediate past history. 

Amongst the species of the Arid Zone, mensural variation, which is 
indubitably clinal in form, affects few species, the most notable of which 
is the Pale-winged Starling Onychognathus nabouroup, an endemic 
extending narrowly from coastal desert Angola to the Karoo of the Cape, 
where it meets and interdigitates with the nominate race of the Red- 
winged Starling O. morio. In nabouroup, size reaches its maximum in the 
southern Karoo, declining northwards through Namibia to terminate in 
southwest Angola, the size gradient not being visibly stepped at any point. 
However, the starkly whiter webs of the remiges of the northern desertic 
populations (O.n. benguellensis) in newly moulted condition can be 
invoked in the upholding of the 2 subspecies accepted by most workers 
{pace Craig 1988). In a second case, the extensive range of the nominate 
subspecies of the Short-toed Rockthrush Monticola brevipes extends from 
the mid- and lower reaches of the Orange R. through Namibia to the 
coastal desert of Angola. The northern populations of M.b.brevipes 
average slightly paler than the southern ones, while the males of the 
Angolan coastal deme frequently display a pale central chin-stripe. 
Study, however, has indicated that subdivision of the nominate race is not 
justified, as the colour transition is essentially clinal and too slight to 
warrant nomenclatural recognition, and as for the chin-stripe in males, its 
limited occurrence in the Angolan coast series available does not merit its 
use. Accordingly, the proposed northern minor race of M.b. kaokoensis is 
not currently recognised and is treated as part of nominate brevipes. 

A great measure of so-called clinal colour-variation in dry country 
birds with an extensive continuum of populations in a continental land- 
mass is in the form of stepped yet graded mosaic-like progressional 
change involving either single or combinations (suites) of variables. A 
tendency to form a clinal disposition may only affect a lone variable in a 
species and not the other characters. The patterns are normally closely 
concordant with local precipitation or vegetational (major biome) con- 
touring, and are phenotypically correlated as a result. As mentioned 
earlier, in the arid country and its periphery, steps and local disruptions 

Bull. B.O.C. 1 1 2A 83 Subspeciation in southern Afrotropics 

in the various character gradients allow of the recognition of some 3-4 
subspecies in moderately polytypic species, the pattern being dark in the 
south and southeast to a pale extreme in close association with almost 
absolute desert in the northwest. Size shifts pursue a closely similar 
pattern, with large elements in the cooler south and smaller sized ones in 
the northwest. Dismissal of variation as simply clinal, thus denying it any 
formal taxonomic recognition, is frequently based on study of severely 
limited material, too often collected in a narrow zone of secondary inter- 
gradation or on the step of a gradient. Such, assuredly, does not fulfil the 
scientific requirements needed for the determination of a true cline as 
envisaged by Huxley. 


In relation to the above issues, the resident bird fauna of the areas of 
Africa lying to the south of the Limpopo and Orange Rivers furnishes a 
lucrative field for investigative research. In his highly instructive paper 
on hybrid (contact) zones in Australian birds, the late Julian Ford (1987) 
describes them in his 'Introduction' as "regions of steep genetic and 
phenotypical intergradation between relatively uniform contiguous 
populations", going on to state that morphological change across 
geographical fronts may arise locally through selection by an environ- 
mental gradient without the involved populations having been previously 
isolated. As a result primary and secondary contact zones may be difficult 
to distinguish. The following includes only some of the contact zones 
identified more recently in southern Africa. 

The White-eye Zoster ops spp. complex resident in the south of and to 
the south and east of the South West Arid Zone has, in the western 
populations in which the ventral yellow is restricted to the throat and 
under tail-coverts, the mid-ventral surface white tinged laterally with 
buff or grey. To the east of these elements occur 2 plexuses of birds 
with the entire under-parts yellow. One of these is morphologically part 
of the western oriented Z. pallidus (the subspecies Z.p. virens and Z.p. 
caniviridis) , while the other is part of Z. senegalensis, which lies spatially 
removed from Z.p. virens and caniviridis, though just impinging on the 
former in lowland Zululand. These last mentioned 2 forms hybridize in 
depth in a contact zone over the Drakensberg Mtns with the western 
white-bellied forms. This contact zone derives from an earlier invasive 
thrust by an ancestor of senegalensis, the descendants of which in contem- 
porary mode furnish, as stated, a further secondary but largely detached 
convergence on the southern African endemic complex of Z. pallidus. 

An instructive mosaic of secondary contacts between close congenerics 
is that of the tightly-knit South African ranges of Pycnonotus capensis, P. 
nigricans and P. barbatus, with only limited hybridization between the 
individual paraspecies at points along their range interfaces. An analo- 
gous combination is also furnished by the batis forms Batis pririt, B. 
molitor and B. soror, which range within current limits from Namibia 
and the Cape east to Mozambique, replacing one another parapatrically 
without hybridization where their ranges converge. B. soror is a Miombo 
savanna monotypic endemic, whereas pririt and molitor are polytypic 

P. A. Clancey 84 Bull. B.O.C. 1 12A 

species of Acacia and bushveld savanna woodlands. Here, it is worth 
pointing out again the hybridizing of the Camaroptera spp. forms in the 
upper Save (Sabi) R. drainage; and allude to the hybridization between 
the parrots Poicephalus cryptoxanthus and P. meyeri from southeastern 
Zimbabwe to the northeastern Transvaal and adjacent Mozambique (see 
Clancey 1977). This latter case is of significance as meyeri does not 
hybridize with its western allospecies P. rueppellii in Namibia. Among 
the austral African larks one finds a particularly interesting instance in the 
Dune Lark Certhilauda erythrochlamys of the dunes of the Namib Desert 
in Namibia, which at some stage expanded its range into the extremely 
arid lower Orange R. basin. The subspecies (or near species) so formed, 
namely C. (e.) burr a, the so-called Red Lark, now hybridizes on its range 
periphery with the Karoo Lark C. albescens, which latter even intrudes 
between burra and the Namibian forms of erythrochlamys (see Clancey 

A re-examination of the variation in the southern populations of the 
Cape Turtle Dove Streptopelia capicola (Clancey 1989a) determined that 
2 of the local races were derived from longstanding and now consolidated 
hybridizing events, both races being distinguishable from either of the 
parental forms. 

In the subspecific interpretation of variation in the Ground 
Woodpecker Geocolaptes olivaceus mentioned earlier, this resulted from 
early splitting of populations between western and eastern faunal refugia, 
occasioned by the spread of aridity during the Quaternary. The descend- 
ants now meet in a broad zone of secondary contact in the eastern Cape. 

In cases of what is in effect secondary contact, the contending taxa may 
not necessarily be physically contiguous, being segregated by an intrusive 
stretch of untenanted terrain, well shown in the range map of the 2 allo- 
species of Black Korhaans Eupodotis afra and E. afraoides (see Clancey 
1989). In such cases it seems as if the descendants of the initial coloniz- 
ation have withdrawn in the face of the expanding and dynamic secondary 
colonist. On the other hand, such a range hiatus may have resulted from 
selection against the resulting hybrids from direct physical contact at an 
early stage. Further and more detailed investigative research into this 
detached form of contact by closely allied taxa, of which several others 
have so far been identified, may help shed some additional light on the 
possible evolutionary mechanisms involved in their formation. 


The Southern African Subregion with its involved mosaic of mesic 
habitats distributed to the north, east and south of an extensive arid 
zone, which varies from dry savanna and steppe-like conditions to near 
absolute desert along the western seaboard, supports a large and varied 
avifauna, of which some 70% of the 170 determined endemics of the 
entire subregion are peculiar to the arid sector, namely the South West 
Arid Zone. Many of these have radiated subspecifically in response to the 
long-term environmental stasis of this dry region. The mesic environ- 
ments arcing round this arid sector have by contrast many fewer endemic 
species; yet the mesic avifauna is both integrally varied and rich. The 

Bull.B.O.C. 112A 


Subspeciation in southern Afrotropics 



in some Southern African Subregion families 

No of 

No. of 

taxa below 


Total of 

No. of 

































Sylviidae (excluding 

the Cisticolidae) 





Fringillidae (genera Serinus 
and Poliospiza) 





Note. Comparable data for other families can be computed from the S.A.O.S. Checklist of 
Southern African Birds (Clancey 1980) and the revisionary updates of 1987 and 1991 . 

comparative shortfall in endemic species is a result of the major climatic 
and vegetational events of Quaternary times. 

The magnitude of the resident bird fauna of the Southern Afric- 
Subregion and its wide range of environments translate into a wealth of 
subspeciation, as shown in examples in Table 1. Comparable data for 
other families can be computed from the S.A.O.S. Checklist of Southern 
African Birds (Clancey 1980) and the revisionary updates of 1987 and 

Clines (sens, strict Huxley 1939) affecting both mensural and colour 
variables have been found to be limited in the avifauna present south of 
16° S in Africa, and restricted to the South West Arid Zone. No cases 
have been found among residents in the various mesic vegetational types 
distributed peripherally to the arid country, assuredly due to the funda- 
mental climatic shifts during the Quaternary and attendant subsequent 
vegetational and other ecological changes. 

Variation, often interpreted as on a cline, may, on critical study, be 
found to consist of a suite of variables rather than a single one, and 
disposed mosaically through the entire plexus of populations. In such 
instances, a clinal style of progressional character shift will normally only 
affect a single criterion, which, unless stepped at some point, may be 
disregarded for formal taxonomic purposes. 

In examples of primary and secondary contact zones south of 16° S, 
most of them researched in depth, so far occur in the southeastern low- 
lands, with some clearly linked to the termination of the Julbernardiaj 
Brachystegia (Miombo) savanna on the Limpopo. Most are seemingly 
cases of primary contact. The Cape Province boasts of a range of second- 
ary contacts, as in the Ground Woodpecker Geocolaptes, while among the 
3 Pycnonotus bulbuls, the paraspecies clearly furnish an example of 

P. A. Clancey 86 Bull. B.O.C. 112A 

secondary contact with minimal hybridization at the interfaces of the 
ranges. In yet other instances, the taxa are in close geographical but 
not direct physical contact, and are effectually allospecies, narrowly 
segregated from one another by untenanted country. The reasons under- 
lying this latter aborted type of contact are as yet only speculative. 


Clancey, P. A. 1970. Comments on some anomalous Bleating Bush Warblers from eastern 
Rhodesia. Durban Mus. Novit. 8(17): 335-337. 

— 1973. A new race of Lamprotornis mevesii (Wahlberg) from north-western South-West 

Africa and adjacent Angola. Durban Mus. Novit. 9(18): 279-283. 
— 1977. Variation in and the relationships of the Brownheaded Parrot of the Eastern African 
Lowlands. Bonn. Zool. Beitr. 28(3/4): 279-291. 

— (Ed.) 1980. S.A.O.S. Checklist of Southern African Birds. Southern African 

Ornithological Society, Johannesburg. 

— 1985. Species limits in the Long-billed Pipits of the southern Afrotropics. Ostrich 56: 


— 1986. Endemicity in the Southern African avifauna. Durban Mus. Novit. 13(20): 


— 1986a. Further comment on variation in the Afrotropical Redeyed Dove Streptopelia 

semitorquata (Ruppell), 1837. Durban Mus. Novit. 14(2): 9-13. 

— 1988. Variation in the Ground Woodpecker Geocolaptes olivaceus. Bull. Brit. Orn. CI. 

108(2): 93-98. 

— 1989. Four additional species of southern African endemic birds. Durban Mus. Novit. 

14(7): 140-152. 

— 1989a. The status of Streptopelia capicola onguati Macdonald, 1957. Bull. Brit. Orn. CI. 

109(4): 225-227. 

— 1989b. Taxonomic and distributional findings on some birds from Namibia. Cimbebasia 

11: 111-133. 

— 1990. The generic status of the Buff-streaked Chat of the Southern Afrotropics. 

Le Gerfaut 80: 179-186. 

— 1991 . The generic status of Roberts' Prinia of the south-eastern Afrotropics. Bull. Brit. 

Orn. CI. 111(4): 217-222. 
Clancey, P. A. & Irwin, M. P. S. 1978. Species limits in the Nectarinia afrajN. chalybea 

complex of African doublecollared sunbirds. Durban Mus. Novit. 11(20): 331-351. 
Craig, A. J. F. K. 1988. The status of Onychognathus nabouroup benguellensis (Neumann). 

Bull. Brit. Orn. CI. 108(3): 144-147. 
Earle, R. A. 1986. Reappraisal of variation in the Ground Woodpecker Geocolaptes olivaceus 

(Gmelin) (Aves: Picidae) with notes on its moult. Navors. Nas. Mus. Bloemfontein 5(7): 

Ford, Julian, 1987. Hybrid Zones in Australian Birds. Emu 87: 158-178. 
Hoesch, W. & Niethammer, G. 1940. Die Vogelwelt Deutsch-Sudwestafrikas. 

J.f. Orn. 88, Sonderheft. 
Huxley, J. S. 1939. Clines: an auxiliary method in taxonomy. Bijdr. Dierk. 27: 491-520. 

Note: An extended list of additional references dealing with subspecific variation and 
particularly endemicity in southern African birds may be found in Clancey (1986). 

Address: Dr P. A. Clancey, Research Associate, Durban Natural Science Museum, P.O. 
Box 4085, Durban 4000, South Africa. 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 87 C. H. Fry 

Myrmecophagy by Pseudochelidon eurystomina 
and other African birds 

by C. H. Fry 

Received 10 March 1992 

Feeding upon dangerously venomous prey such as Hymenoptera, 
scorpions and snakes must present birds with problems, the adaptive 
morphological and physiological solutions to which have not received a 
great deal of attention from ornithologists. Although ants (Formicidae), 
some other hymenopterans, and termites (Isoptera) are abundant in 
humid regions, birds that exploit them for food incur a further set of 
problems arising from their prey's swarming and patchy distribution. 
Some aberrant social and behavioural adaptations of such specialist bird 
species are already known and more may be expected to be found. For 
both reasons, physiological and sociobiological, myrmecophagy or ant- 
eating by birds should be of interest. This paper adds a swallow to the 
known 'professional' myrmecophages amongst African birds, and briefly 
reviews ant predation in African nonpasserine and several passerine 

Pseudochelidon eurystomina 

The African River Martin P. eurystomina is an aberrant swallow or 
swallow-like bird generally placed in the hirundine subfamily 
Pseudochelidoninae, of which the only other species is P. sirintarae. The 
latter was discovered in 1968 and is known only from the few birds that 
wintered at Bung Boraphet reservoir in central Thailand 1968—1980; it 
has not been seen since (Turner & Rose 1989). Chapin (1953) provided 
the basis of knowledge about P. eurystomina, about which rather little is 
still known (Keith et al. 1992), although further observations have 
recently been made at a breeding colony near Animba, Port Gentil 
(0°58'S, 8°54'E), Gabon, September-October 1989 (Alexander-Marrack, 
in press). Its known breeding range is the middle and upper Congo River 
and the lower Oubangui River where it occurs from January to April- 
May, and near the coast of Gabon and Congo Republic where it occurs 
only from May/June to November, breeding September-October. There 
is some evidence of migration between the interior and coastal regions 

The species is thought to forage exclusively on the wing, and its flight 
actions are reminiscent more of American Progne martins than of typical 
Hirundo swallows. Dense flocks fly with the co-ordinated precision of 
European Starlings Sturnus vulgaris (Brosset & Erard 1986); almost 
nothing else is known about the social organization of this swallow. 

Materials and methods 

P. Alexander-Marrack made a small collection of faeces and regurgi- 
tates (pellets) at the Animba colony and enabled me to examine them. 

C. H. Fry 88 Bull. B.O.C. 1 12A 


Prey of Pseudochelidon eurystomina, Animba, Gabon, 1989: (a) faeces, 24 September, (b) 

regurgitates, 1 October, (c) regurgitates, 1 5 October 

Approx. no. 

























































Other Hymenoptera 














Faeces are straight or curved cylinders 2.0-3.2 mm in diameter, found in 
pieces up to 9 mm long, consisting of densely-packed blackish sclerites in 
a sleeve of white crystalline uric acid. They were teased by hand and 
heated to 40°C in glycerol for 5 hours to dissolve the uric acid. Insect head 
capsules, mandibles, wings and some other recognizable fragments were 
sorted by hand and identified taxonomically by reference to the literature 
and insect collections at Sultan Qaboos University, Oman. Apart from 
loss of antennae, setae and some mouthparts, head capsules were rarely 
damaged; many even retained antennae and all mouthparts. 

The regurgitates consisted of 10-12 ovoid or subspherical dry blackish 
pellets measuring 6—7 x 10—11 mm, and together weighing 1.4 g. They 
were moistened with ethanol and divided into 26 subsamples which were 
teased and sorted by hand in ethanol using a high-powered dissecting 
(binocular) microscope. After removal of insect head capsules, 5 
subsamples were re-examined and the number of further head capsules 
recovered indicated that at least 95% of them had been recovered in the 
initial search. 


Regurgitates and faeces consist entirely of insect remains. More than 
1000 head capsules were recovered, in proportions of taxa that differed 
substantially between the 3 samples (Table 1). In total, ants 
compose about 65% of the diet of P. eurystomina, other hymenopterans 
9%, termites 24%, and all other insect Orders only about 2%. A few 
almost entire ants present in pellets were identified from keys in 
Holldobler & Wilson (1990) as species of Camponotus (Formicinae) and 
Crematogaster, Monomorium and Pheidole (Myrmicinae). Other ants were 
not identified to genera. At least 1 7 types or genera of ants were evident in 
the samples, but many of the 32 apparent taxa and 89 specimens of 'other 
Hymenoptera' may well have been ants also, to judge from descriptions of 
head capsules in Holldobler & Wilson. 29% of the ants appeared to 
belong to a single (unidentified) taxon and 43% to 5 others. 

Bull.B.O.CAUA 89 Myrmecophagy 

Six whole ants were 6, 6, 7, 8, 9 and 10 mm long. Widths of ant head 
capsules, in relation to the head size and body lengths of the whole ants, 
suggested that the majority of ant prey were c. 8 mm long. Largest prey 
items were a damselfly (Odonata) probably > 30 mm long and a sphecid 
wasp probably 13— 16 mm long. At the other extreme, some hymen- 
opteran heads were only 0.3 mm in width so that the whole insect may 
have been no more than 2 mm long; and an entire beetle was only 2.2 mm 

Predation on ants by African birds 

Information on diets of birds in Africa has been obtained mainly by 
museum skin collectors, economic biologists studying waterfowl, 
gamebirds and agricultural pests, and ornithologists reporting on gizzard 
contents of road kills or analysing regurgitated pellets. The literature, 
which is large and diffuse, has been reviewed in The Birds of Africa (Vols 
1-4: Brown et al. 1982, Urban et al. 1986, Fry et al. 1988, Keith et al. 
1992), with accounts of 1187 species, including all of the nonpasserines 
and the passerines from Eurylaimidae to Myrmecocichla in Turdidae. 
There are c. 864 remaining passerines (Monticola, Zoothera, Turdus, 
warblers, flycatchers, sunbirds, shrikes, starlings, weavers, finches etc.), 
for which no data have been collected, and to that extent this review and 
Table 2 are incomplete. Neither primary literature sources, nor such 
essentially extra- African works as The Birds of the Western Palearctic (see 
especially Vol. 5, Cramp 1988), have been utilized. In the latter work, 
food data from Africa for species that visit or reside there are summarized 
in The Birds of Africa; food data from Europe are somewhat peripheral to 
this paper and in general have been ignored. Many taxa are not implicated 
in ant-eating at all: they are listed in the Appendix and, excluding 194 
fully aquatic foragers, they represent 359 species. 

Table 2 lists 116 genera, each with one or more species that eat ants. 
The genera include 622 African species, of which 272 eat ants — that is 
28% of the terrestrial avifauna (359 + 622 species) reviewed to date. It is 
likely that most congeners of ant-eating species will eventually be found 
to eat ants also, occasionally if not regularly. In that event the proportion 
of myrmecophagous species in the terrestrial avifauna could prove to 
exceed 60%. 

Major ant predators 

Fifty-five species are identified as major ant predators in Table 2 (quo- 
tations are from The Birds of Africa). 

PHASIANIDAE Alectoris barbara: "Seeds, fruits and leaves, sup- 
plemented by insects, especially ants . . . food of young often mainly 
ants". Francolinus lathami: "90% arthropods, especially termites 
Basidentitermes spp. and ants Psalidomyrmex spp.". F. levaillantii: 
70—80% of the crop volume is vegetable matter, and the rest of the diet is 
"mainly ants, spiders, grasshoppers, millepedes and beetles". F. capensis: 
vegetable matter and "insects (especially termites and ants)". Phasianids 
in general and francolins Francolinus in particular appear to be important 
ant predators. 

C. H. Fry 


Bull.B.O.C. 112A 


Genera and numbers of species of African birds known to eat ants 

(from The Birds of Africa 1-4) 

and genus 

Numbers of species 
in known to major ant Family 

Africa eat ants predators and genus 

Numbers of species 
in known to major ant 
Africa eat ants predators 
















A lee tor is 

































r 1 tKU^LllJ At 


































1 Cypsiurus 



3 Apus 























1 Eurystomus 






























































Continued on next page 

Bull.B.O.C. 112A 



TABLE 2. (cont.). 

Numbers of species 

Numbers of 




known to 

major ant Family 


known to 

major ant 

and genus Africa 

eat ants 

predators and genus 


eat ants 






















































































































Ale the 























































OTIDIDAE Chlamydotis undulata: vegetable matter, "small invertebrates 

especially ants and beetles, and small reptiles". 

CHARADRIIDAE Lapwings Vanellus probably eat significant amounts of 


LARIDAE Larus audouinii: "Of 120 Apr-June pellets from Morocco, 87% 

contained fish, 5% insects . . . insects were winged ants (40%)". 

CAPRIMULGIDAE Of 23 nightjar species, 9 are known to eat alate ants, of 

which these birds are probably major predators. 

APODIDAE Of 21 species, no less than 18 eat ants, and swifts are probably 

even more important myrmecophages than nightjars. 

MEROPIDAE 10 out of 18 African bee-eaters consume ants. Merops 

albicollis: Nigerian pellet samples "(n=1700 insects) were ... ants 

(overall 56%)" and Ivory Coast gizzards "(n=1500 insects) were 55% 

ants (1 gizzard with 200 Crematogaster ants). Flying termites not 

commonly eaten". M. orientalis: "Airborne insects: 75% Hymenoptera 

. . . mainly ants". M. malimbicus: "Flying ants (70% of 1250 prey items, 

C. H. Fry 92 Bull. B.O.C. 1 1 2A 

R. Niger)". Further details of ant-eating in African bee-eaters are given 
by Fry (1984). 

CORACIIDAE Coracias rollers may be important predators of ants, but, 
certainly, few African genera are more so than the broad-billed rollers 
Eurystomus. E. gularis: "Flying ants (91 % of 3623 items in 20 stomachs, 
mainly Crematogaster, also Oecophylla), flying termites 3%". E. 
glaucurus: "Specialises on swarming winged ants (e.g. Crematogaster , 
Oecophylla) and termites (e.g. Macrotermes, Pseudacanthotermes). 1644 
insects from stomachs were: ants 66%, termites 15%". "Up to 280 birds 
quickly assemble at a large hatch and feed . . . with swifts and swallows 
. . . [each catching] 6-10 [insects] per min . . . normally 200-^-00 and 
sometimes 600-800 insects" (Thiollay 1970). 

BUCEROTIDAE and CAPITONIDAE Ground- and tree-feeding hornbills 
(Tockus, Ceratogymna) and ground-feeding barbets (Trachyphonus) may 
be major ant predators. 

PICIDAE Both species of wrynecks, jfynx, all 10 species of the endemic 
woodpecker genus Campethera, the ground woodpecker Geocolaptes 
olivaceus, and the only African species of Picus, are predominantly 
myrmecophages. jfynx torquilla: "Mainly ants, up to 500 reported in 1 
stomach . . . young fed on adults, pupae, larvae and eggs of ants." J. 
ruficollis: "Mainly ants, their larvae, pupae [and] eggs . . . from ant nests 
in the ground, also on trees . . . the small ants Pheidole megacephala 
and Crematogaster castanea made up c. 88% of diet (Tarboton 1976)". 
Campethera punctuligera: "Stomachs (n = 25) contained only ants, their 
larvae and pupae, and in 5 cases, termites". C. abingoni: "Almost entirely 
ants, their pupae, larvae and eggs". The other Campethera species are 
reported in like vein, although their diets are less well known. Geocolaptes 
olivaceus: "Entirely ants (pupae, larvae, eggs, adults) of various un- 
identified spp.". Picus viridis: "Major food, ants (Camponotus nylanderi, 
Crematogaster scutellaris) y \ 

ALAUDIDAE Six lark genera are not yet known to eat ants in Africa; 13 
genera are known to, and of their 57 species, 24 (42%) take ants and 3 
or more could be major predators. Mirafra apiata: "Ants . . . and . . . 
termites (Hodotermes mossambicus)". Certhilauda curvirostris: "Insects 
(termites, including Microhodotermes viator . . . ants Tetramorium and 
Anoplolepis)". C. albescens: ants include Messor, Pheidole, Tetramorium, 
Crematogaster and Acantholepis. Chersomanes albofasciata: "Insects, <$$ 
eat more tenebrionid beetles, 99 more ants and harvester termites". Spi- 
zocorys sclateri: invertebrates — caterpillars, small beetles, "ants 
(Messor capensis, Monomorium spp.)". 

HIRUNDINIDAE Like other small-billed aerial insectivores (nightjars, 
swifts), most swallows almost certainly consume large numbers of ants in 
Africa as they are known to do elsewhere (Turner & Rose 1989). Detailed 
investigations of most species have been lacking in Africa. An exception 
is Hirundo spilodera, in which the main prey are beetles, flies and wasps. 
Ten species of ants occurred in 4—16% of stomachs (genera Simonopone , 
Messor, Pheidole, Solenopsis, Tetramorium, Triglyphothrix , Anoplolepis, 
Camponotus) and Camponotus maculatus occurred in 36% of another 
sample (Earle 1985). Diets of the swallows Phedina and Pseudhirundo are 
unknown; the 5 other genera all catch ants, and of their 35 species at least 

Bull. B.O.C. 112A 93 Myrmecophagy 

15 (43%) do so. Major predators are Pseudocalyptomena eurystomina, 
whose diet is 65% ants, 8% other hymenopterans and 24% termites, 
and 2 more species of Hirundo. H. daurica: "Not studied in Africa, but 
in France 25-day nestlings were fed 255 items, 94% winged ants". H. 
rustica: food in Africa is very varied and includes arillate seeds. Ants 
feature as follows: "Small airborne insects, mainly ants, flies and beetles 
(25 birds, Uganda) ... 4 birds, Orange Free State, each contained 17-120 
ants [only] ... 2 road kills, Kenya, contained ... 22 winged ants [and 43 
other insects] . . . casualties at a Zimbabwe roost had stomachs packed 
solid with small flying ants". 

MOTACILLIDAE Anthus cervinus: "Insects and their larvae (especially 
ants, beetles, flies)". 

PYCNONOTIDAE 19 out of 44 species in 8 genera are known to eat ants and 
3 other genera are not yet implicated. Andropadus and Phyllastrephus , 
with 5 ant-eating species each, may be important. All 3 Bleda species 
eat ants. P. terrestris: "Arthropods, including insects . . . especially 

TURDIDAE Of the 26 African genera, only 3 (Monticola, Zoothera, Turdus) 
have not been dealt with in The Birds of Africa so far. Five of them are not 
yet known to eat ants: Cichladusa (with 3 species) and the monotypic 
Cossyphicula, Modulatrix, Arcanator and Pinarornis. Of the other 18 
genera, 67 of their 91 species (74%) take ants, and 21 or more species are 
major predators. The endemic alethes Alethe habitually attend army ant 
swarms in forest; the 5 Alethe species eat some army ants (Dorylus), but 
they depend mainly on other invertebrates that the army ant columns 
flush. Some species of Neocossyphus are known as ant-thrushes and some 
of Myrmecocichla as anteater-chats, with good reason. Robins, and robin- 
chats Cossypha, are particularly important ant predators (Oatley 1970, 
1992). Pogonocichla stellata: ants were found in 43% of faecal samples 
in Natal (but were outnumbered by moths and particularly beetles). 
Swynnertonia swynnertoni: "In 25 stomachs and 4 faeces (Chirinda, 
Zimbabwe), there were beetles in 93%, ants in 55% ... In 20 [other] 
stomachs, beetles and ants made up 72%". Erithacus rubecula: food in 
North Africa has not been studied but in south Spain in one study "of 
> 1900 invertebrates 76% by number were ants". Cossphya caff r a: in 104 
samples mainly from Natal "ants occurred in 88%". C. humeralis: in 38 
samples "there were beetles in 63%, ants in 55%"; this robin-chat also 
eats termites, spiders, fruits, etc. C. heuglini: in 28 samples from Zaire, 
Zambia, Malawi and Zululand there were "ants (Ponerinae, Dorylinae, 
Camponotinae, Myrmicinae) in 86%". C. natalensis: in 47 samples from 
5 countries there were "beetles ... in 79%, ants in 77%" and smaller 
percentages of other invertebrates and fruits. C. dichroa: in 44 samples 
"from Natal and Transvaal there were beetles in 73%, ants in 61%, 
moths and caterpillars in 34%" etc. C. heinrichi: "Principally ants, 
including doryline driver ants". Alethe poliophrys: "Insects, including 
beetles, flies and army ants (60-80 in one stomach . . .)". Neocossyphus 
poensis: "insects, larvae and pupae (ants, including army ants; termites, 
beetles, grasshoppers)". Cercotrichas quadrivirgata: in 21 samples from 
Malawi and Natal there were beetles in 76%, ants in 71%, termites in 
48%, etc. C. signata: analysis of 27 samples showed that "ants (63%), 

C. H. Fry 94 Bull. B.O.C. 112A 

beetles (59%), and millipedes (48%) are the most frequent prey". C. 
leucophrys: in 51 "samples from southern Africa there were: termites in 
69° , ants in 67%, beetles ... in 59%", etc. C. paena: "In 8 stomachs 
(Botswana, Transvaal) there were: termites ... in 100%, beetles ... in 
62%, ants (Ponerinae, Myrmicinae) in 62%", etc. Phoenicurus moussieri: 
"Insects, mainly ants, beetles, grasshoppers and larvae". Although all but 
one of the 17 wheatears Oenanthe in Africa are known to eat ants, there are 
few quantitative data and only 3 species seem to be major predators of 
ants. Oenanthe leucura: "Mainly insects, especially beetles and ants". O. 
lugens: "Mainly ants; also beetles, grasshoppers and other insects". O. 
pileata: "Insects, especially ants, also flies, locusts", etc. Myrmecocichla 
formicivora: "Insects, especially ants and termites. In 33 birds near 
Bloemfontein, South Africa, Hymenoptera (almost all Formicidae) 
dominated numerically in summer, and they and termites (entirely 
Hodotermes) in winter" (Earle & Louw 1988). (The diet of M. aethiops, 
the Northern Anteater-Chat, has not been quantified; it is doubtless 
much like its allospecies A. formicivora.) M. arnotti: "Insects and spiders, 
especially ants". 


Chapin (1953) reported that Pseudochelidon eurystomina feeds entirely on 
the wing and that stomachs contained a few Hemiptera, Homoptera, 
beetles, flies and small butterflies, and many alate ants. Recent observers 
also report that this aberrant swallow forages largely if not exclusively in 
flight; and Chapin's early diagnosis about its diet is amply confirmed by 
the present study. 

Ants are an abundant, diverse, and conspicuous component of the 
tropical insect fauna, in savanna grassland and woodland as well as in 
rainforest. It is thus not altogether surprising to find that 28% (and 
possibly >50%) of the terrestrial bird fauna exploit them. However, 
it is remarkable that as many as 55 species appear to be specialist 
myrmecophages, a number that can only rise when information on the 
864 uninvestigated passerines becomes available. 

Major ant predators fall into 3 principal guilds: aerial hunting of alate 
ants, tree bark probing, and ground foraging on mainly non-alate ants. 

Aerial predators are the nightjars, swifts, bee-eaters, Eurystomus 
rollers, and swallows. The rollers forage only at mass crepuscular swarms 
of ants and termites. Swifts and swallows feed at swarms, but also on 
dispersed flying ants and other small insects. Nightjars (crepuscular and 
nocturnal) and bee-eaters (diurnal) seem to feed mainly on ants and other 
insects that are dispersed and not swarming. 

The bark-probing guild includes wood-hoopoes and 3 genera of strongly 
myrmecophagous woodpeckers. They forage by probing and gleaning 
mainly woody vegetation; they also probe ants' nests in the ground {Picus), 
and hop on the ground to glean it near the bases of trees (Jynx y several 
species of Campetherd). Woodpeckers (Picinae), of course, provide the one 
avian example of gross anatomical adaptation to myrmecophagy, with their 
thick skin, sticky saliva, hyoid horns, and extraordinarily long, worm-like, 
protrusible, mobile and barb-tipped tongues. 

Bull.B.O.CAUA 95 Myrmecophagy 

Ground foragers include a fourth woodpecker genus, the exclusively 
myrmecophagous Geocolaptes, which feeds gregariously in large 
territories, using a sentry, progressing mainly by hopping. The bulbul 
Phyllastrephus terrestris is another ant-eater that forages in small groups 
on the ground, by hopping. Several Tockus hornbills search the ground 
by active (if rather clumsy) hopping-running. All other species in this 
guild are quite long-legged walkers or hoppers, like larks, pipits, robins, 
chats and thrushes. They may be soft-billed or hard-billed. Most ants 
being small, there appears to be a body-size constraint to myrmecophagy 
among their avian predators, with few being larger than francolins (500 g) 
or even than lapwings (250 g). Bustards and Ceratogymna hornbills, 
ground and arboreal foragers respectively, are exceptionally large; 
ants, some of which may be eaten adventitiously, do not feature to any 
significant extent in their diets. 


I thank R. Gabor, S. M. Head and D. Roberts who have helped in various ways with 
this study, and I am particularly grateful to P. Alexander-Marrack for providing the 
P. eurystomina material. 


Alexander-Marrack, P. (in press). Notes on a breeding colony of the African River Martin 

Pseudochelidon eurystomina in Gabon. Malimbus. 
Brosset, A. & Erard, C. 1 986. Les Oiseaux des Regions Forestieres du Nord-Est du Gabon. Vol. 1 . 

Ecologie et comportement des especes. Societe Nationale de Protection de la Nature, 

Brown, L. H., Urban, E. K. & Newman, K. (eds) 1982. The Birds of Africa, Vol. 1. 

Academic Press, London. 
Chapin, J. P. 1953. The Birds of the Belgian Congo, Part 3. Bull. Amer. Mus. Nat. Hist. 75A: 

Cramp, S. (ed.) 1988. The Birds of the Western Palearctic, Vol. 5. Oxford University Press. 
Earle, R. A. 1 985 . Foraging behaviour and diet of the South African Cliff Swallow Hirundo 

spilodera (Aves: Hirundinidae). Navors. Nas. Mus. Bloemfontein 5(4): 53—66. 
Earle, R. A. & Louw, S. v.d. M. 1988. Diet of the anteating chat Myrmecocichla formicivora 

in relation to arthropod abundance. <S. Afr.J. Zool. 23(3): 224-229. 
Erard, C. 1981. Sur les migrations de Pseudochelidon eurystomina Hartlaub au Gabon. 

Oiseau etR.F.O. 51: 244-246. 
Fry, C. H. 1984. The Bee-eaters. T. & A. D. Poyser, Calton, U.K. 
Fry, C. H., Keith, S. & Urban, E. K. (eds) 1988. The Birds of Africa, Vol. 3. Academic Press, 

Holldobler, B. & Wilson, E. O. 1990. The Ants. Belknap Press of Harvard University Press, 

Cambridge, Mass. 
Keith, S., Urban, E. K. & Fry, C. H. (eds) 1992. The Birds of Africa, Vol. 4. Academic Press, 

Oatley, T. B. 1970. Observations on the food and feeding habits of some African robins 

(Aves: Turdinae). Ann. Natal Mus. 20(2): 293-327. 
Oatley, T. B. 1992. Turdidae (in part), in Keith, S. et al. (eds) The Birds of Africa, Vol. 4. 

Academic Press, London. 
Tarboton, W. 1976. Aspects of the biology of jfynx ruficollis. Ostrich 47: 99-112. 
Thiollay, J. M. 1970. L'exploitation par les oiseaux des essaimages de fourmis et termites 

dans une zone de contact savane-foret en Cote d'lvoire. Alauda 38: 255-273. 
Turner, A. & Rose, C. 1989. A Handbook to the Swallows and Martins of the World. 

Christopher Helm, Bromley, U.K. 
Urban, E. K., Fry, C. H. & Keith, S. (eds) 1986. The Birds of Africa Vol. 2. Academic Press, 


(\ II. Fry 96 Bull. B.O.C. 11 2A 


Taxa in The Birds of Africa (Vols. 1-4) not implicated in ant-eating 

dae, Balaenicipitidae, Plegadis, Bostrychia, Platalea, PHOENICOPTERIFORMES, 
FALCONIFORMES, Acryllium, Ptilopachus, Ortyxelos, Rougetius, Rallus, Porzana, 
Aenigmatolimnas , Amaurornis, Porphyrio, Gallinula, Fulica, Gruidae, Heliornithidae, 
Tetrax, Ardeotis, Otis, Jacanidae, Rostratulidae, Dromadidae, Haematopodidae, Recurvir- 
ostridae, Burhinidae, Pluvianus, Charadrius, Pluvialis, Scolopacidae, Stercorariidae, Rissa, 
Gelochelidon, Sterna, Anous, Rynchopidae, Alcidae, Treton, Turtur, Oena, Columba, PSIT- 
TACIFORMES, MUSOPHAGIFORMES, Oxylophus, Clamator, Pachycoccyx, Chryso- 
coccyx, Ceuthmochares, Tytonidae, Otus, Jubula, Bubo, Scotopelia, Athene, Strix, Asio, 
Zoonavena, Urocolius, Trogonidae, Alcedininae, Cerylinae, Bucorvus, Gymnobucco, Prodo- 
tiscus, Melignomon, Lullula, Alauda, Eremophila, Phedina, Pseudhirundo , Tmetothylacus , 
Campephaga, Lobotos, Calyptocichla, Chlorocichla, Pyrrhurus, Bombycillidae, Cinclidae, 
Troglodytidae, Prunellidae, Cossyphicula, Modulatrix, Arcanator, Pinarornis, Cichladusa. 

Address: C. H. Fry, Department of Biology, College of Science, Sultan Qaboos University, 
Box 32486 Al Khod, Sultanate of Oman. 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 97 P. R. Grant 

Systematics and micro-evolution 
Peter R. Grant 

Received 24 January 1992 


Darwin's theory of evolution by natural selection is the central theory of 
modern biology. It has been greatly modified and extended, for example 
by the facts of genetics and the concept of genetic drift. Nevertheless 
current evolutionary theory is recognizably Darwinian. Contrast this 
with systematics, a field of biology to which evolutionary theory applies. 
Systematics, the study of relationships among organisms, has been more 
than modified, it has been truly transformed, and the transformation has 
occurred relatively recently. For the first three quarters of the past 
hundred years systematists established relationships among taxa by using 
phenotypic data to assess similarities. With the advent of electrophoresis 
in 1966 (Hubby & Lewontin 1966), and subsequent development of bio- 
chemical and molecular techniques like DNA-DNA hybridization, DNA 
fingerprinting, and gene amplification and sequencing, systematics has 
become increasingly grounded in genetics. The second element in the 
recent revolution has been the development of cladistic principles (and 
others) to be used in the reconstruction of phylogenies. An avian systema- 
tist of the 1 890s, allowed a return visit in the 1 990s, would be delighted to 
see that a classification of all 9672 bird species of the world has been 
accomplished (Sibley & Ahlquist 1990, Sibley & Monroe 1990), would be 
pleased to recognize familiar taxonomic categories like species, genera 
and orders, but would be bewildered by the way in which we assign 
particular birds to them. 

Our returning Victorian would be similarly amazed at how the modern 
Elizabethan uses systematic information to gain an understanding of 
evolution. Having identified systematic relationships among taxa we 
would like to know the processes that gave rise to them, by what routes, 
why, where and how quickly. This is a field of inferential investigation of 
past evolutionary processes. It is pursued in various ways. The search for 
fossils is the obvious, but often limited, way. Mathematical modelling can 
help by showing what could have occurred and what could not have 
occurred, given plausible assumptions. Investigation is also popularly 
pursued by studies of contemporary processes; by the study of behaviour, 
ecology and micro-evolution of existing populations, which are the 
products of those past evolutionary processes. 

In this article I will describe how a study of micro-evolution as a con- 
temporary, observable, process has been used to throw light on evolution 
in the past. 


Evolution is organic change, change that takes place from one generation 
to another in the genetic constitution of a population. Small changes 
accumulating over long periods of time give rise to large differences, such 

P. R. Grant 98 Bull. B.O.C. 1 12A 

as those between 2 species in different but related genera or families. 
Micro-evolution refers to the small individual changes. 

I make a distinction between the genetic changes taking place from one 
generation to the next, micro-evolution, and the evolutionary forces such 
as natural selection acting within a generation that produce an evolution- 
ary effect. Natural selection occurs when some individuals in a population 
survive or reproduce better than others because they possess traits that 
enable them to perform better in that particular environment. If there is a 
heritable basis to those traits then the genes governing them will be passed 
on to the next generation. Differential gene transmission to the next gen- 
eration is micro-evolution. Evolutionary processes other than natural 
selection may also give rise to or contribute to micro-evolution: sexual 
selection, mutation, immigration and drift. 

I next make a distinction between selection inferred and selection 

Natural selection and adaptation 

Differences between related taxa are in need of explanation. For example, 
birds on islands are often larger, and have larger beaks, than their relatives 
(same or different species) in nearby continental regions (Murphy 1938, 
Grant 1965). If islands have been colonized by birds from the mainland, 
as is likely to be generally the case, and evolution has been greater in 
the island population than in the mainland population since the time of 
colonization, the traits of the island birds need to be explained. Adaptation 
is suggested when the traits can be associated with some feature of the 
island, for example when beak size can be correlated with food size 
(Grant 1965, 1966, 1968, 1979a,b). The role of natural selection has been 

The functional significance of variation in external traits like beak 
size is relatively easy to assess (Bowman 1961), and this facilitates 
investigation of adaptation (Arnold 1983). The task is much more diffi- 
cult with internal anatomical features. Absence of association between 
trait expression and environmental characteristic suggests that evolution 
has proceeded by random processes like founder effects and drift. Models 
of the expected rate of divergence under drift can be employed to make 
quantitative tests of the drift (or selection) hypothesis (e.g. Baker et al. 

Natural selection as a contemporary process 

The direct study of natural selection requires something very different. It 
requires following the fates of known individuals through time to see if 
success or failure in survival and reproduction (fitness) is associated or not 
with the possession of a trait or the particular expression of a trait. An 
early example is the demonstration in 1974 of non-random survival in 2 
populations of Darwin's Finches on the Galapagos island of Daphne 
Major. Surviving Medium Ground Finches Geospiza fortis had longer 
bill tips than non-survivors, and surviving Cactus Finches G. scandens 
varied less in weight and beak depth than non-survivors (Grant et al. 
1976). The first is an example of directional selection, the second an 
example of stabilizing selection. 

Bull. B.O.C. 1 12A 99 Systematics and micro -evolution 

Since then there have been several studies of natural selection in bird 
populations, carried out mainly in the last dozen years and for different 
purposes. Price & Boag (1987) summarized the first ones, and discussed 
methods of analysis (see also Endler 1986). More recent studies have 
included selection on plumage variation (Moller 1989, Grant 1990, 
Hill 1991), on various morphological attributes including beak size and 
body size variation (Grant & Grant 1989a,b, Smith 1990, Hakkarainen & 
Korpimaki 1991, Witzell 1991) and on migratory tendency (Berthold 

While quantitative, observational, studies such as these are needed to 
document, describe, and measure natural selection, they can do no more 
than suggest the causes of selection. Experiments are required to test 
selection hypotheses that specify causes. 

Heritable variation 

The direct study of micro-evolution requires that there be heritable vari- 
ation. The methods of quantitative genetics have been applied to many of 
the same populations that have been investigated for evidence of natural 
selection. Boag & van Noordwijk (1987) provide a thorough review of 
methods, problems and accomplishments. A general finding has been that 
morphological traits such as beak size and body size have high heritabili- 
ties, whereas life history traits such as clutch size have lower but not 
negligible heritabilities. There is heritable variation in migratory tendency 
(Berthold 1991) and plumage traits (Moller 1989, Grant 1990, Hill 1991). 
Indeed the absence of significant heritable variation for well investigated 
traits (e.g. Gibbs 1988) is the exception rather than the rule, at least 
according to published studies. 


Micro-evolution of Darwin's Finches has been studied on Isla Daphne 
Major. The island is small (0.34 km 2 ), close to the equator in the centre of 
the Galapagos archipelago, and 8 km from the nearest large islands of 
Santa Cruz and Baltra. Two species have resident populations; Geospiza 
fortis (Medium Ground Finch) and G. scandens (Cactus Finch). Two 
others occasionally immigrate and rarely stay to breed: G. fuliginosa 
(Small Ground Finch) and G. magnirostris (Large Ground Finch). Birds 
have been ringed and measured since 1973. Breeding has been studied in 
every year when it has occurred between 1976 and 1991, almost all nests 
have been found, nestlings ringed and the parents identified by obser- 
vation. Harmonic mean breeding population sizes were 197 G. fortis, 94 
G. scandens, 6 G. fuliginosa and 4 G. magnirostris (Grant & Grant 1992). 

Natural selection 

Three episodes of natural selection have been witnessed (Table 1) at 
times of high mortality. The first and strongest occurred from late 1976 to 
the end of 1977. Almost no rain fell between March 1976 and January 
1 978. Of the 640 ringed G. fortis alive at the beginning of this period only 
97 (15%) survived to the end. Mortality was size-selective; large birds 
survived better than small birds. G. scandens experienced a similar 
size-selective mortality, although less intensely. Survival was 42%. 

P. R. Grant 100 Bull. B.O.C. 1 12A 


1 Irritabilities and coefficients of selection for 4 morphological traits of Geospizafortis on Isla 
Daphne Major. Selection coefficients are standardized selection differentials. Sample sizes 
refer to pairs of parents followed by numbers of offspring in the heritability column, and 
numbers of measured birds alive before selection occurred in the other columns. '=not 
significantly different from zero (P>0.05). 


Selection coefficients 

h 2 









Bill length 





Bill depth 





Bill width 





Sample sizes 










Dry conditions occurred again in 1981-1982, and G. fortis was sub- 
jected to the same directional selection, though to a smaller degree than in 
1977. Survival was much higher (65 %) this time. 

The final episode occurred in the aftermath of an extremely severe El 
Nino event in 1 982-83 , which brought an extraordinary amount of rain to 
the Galapagos and resulted in some finches breeding for as many as 8 
times. Breeding occurred twice in 1984, and then not again until 1987, 
another El Nino year, except for attempts made by some individuals in 
1986. During the dry period without breeding from mid-1984 to the end 
of 1985 G. fortis were subjected to natural selection in the opposite 
direction; small birds survived better than large birds. From 1 987 onwards 
mortality has been random with respect to size. 

The targets of natural selection 

When forces of selection act on one trait, other traits which are correlated 
with it are affected. Phenotypic correlations among the measured mor- 
phological traits are all positive and moderately large in the 3 populations 
of Darwin's Finches that have been studied in detail: G. fortis and G. 
scandens on Daphne (Boag 1983) and G. conirostris on I. Genovesa (Grant 
1983). Thus when natural selection occurs, all traits shift in the same 
direction, although to different degrees, and it is not possible to determine 
by inspection .of coefficients of overall selection like those in Table 1 
whether selection acts on one or a suite of traits. 

The problem of identifying the targets of selection is solved by using 
Lande & Arnold's (1 983) multiple regression method which separates the 
direct association between fitness and a trait from the indirect ones, 
arising from correlations among traits (see also Crespi 1990). Price et al. 
(1984a) applied this method to the Daphne data from 1976-77 and found 
that the 4 traits listed in Table 1 were selected in different directions: 
weight and beak depth to increase and beak width to decrease. Beak length 
was not selected at all. Beak width was selected to decrease in 1984-85 as 
well (Gibbs& Grant 1987). 

Identifying the targets helps in the interpretation of selection. Boag & 
Grant (1981) hypothesized that large birds survived the drought of 1977 

Bull. B.O.C. 112A 101 Systematics and micro-evolution 

relatively well in part because, possessing deep beaks, they were able to 
crack the large and hard seeds that remained in moderate abundance after 
the initially large stock of small seeds had been depleted. The analysis of 
targets supports the hypothesis, but reveals other targets not explained 
by it. Similarly Gibbs & Grant (1987) could account for selection in 
the opposite direction in terms of an altered composition of the food 

Heritable variation 

Beak and body size traits display high levels of heritable variation. Boag 
(1983) regressed measurements of fully grown G.fortis offspring on mid- 
parent values to obtain the estimates shown in Table 1 . All are signifi- 
cantly different from zero. Heritabilities of other measured traits, wing 
and tarsus length, are similarly high. 


With such high heritabilities and strong coefficients of selection, 
evolution is expected to occur. The product of the heritability of a trait 
and the selection coefficient gives the simplest prediction of an evolution- 
ary response to selection (Falconer 1 989) . More complicated formulations 
take into account the correlations among traits (Lande 1979, Price & 
Boag 1987). These will be discussed below. Boag (1983) used the first 
component from a principal components analysis of all morphological 
measurements to characterize overall body size, calculated the heritability 
of this synthetic trait (0.75) and the selection coefficient during the 1 976-77 
episode, and predicted an evolutionary response to selection of 0.40 
standard deviations. The actual response in this trait — the difference 
between the population average before selection and the average in the 
next generation born in 1978 — was 0.36 standard deviations, and hence 
close to the predicted amount. Therefore micro-evolution had occurred, 
as predicted: average body size was larger in the next generation as a result 
of a small scale evolutionary change. 

Evolution occurred in the opposite direction in 1984—85. The gener- 
ation born in 1987, like their parents, were smaller on average than the 
population in 1984 before selection had occurred. 

The magnitude of selection and evolution can be most simply 
expressed as a percentage change in the mean of a population. For 
example, the selection episode of 1976-77 resulted in an increase in mean 
beak depth of about 5 % . Evolutionary change was a little more than three 
quarters of this, c. 4%. Selection in the opposite direction in 1984-85 
resulted in a shift in the mean of 2-3 % and an evolutionary change in the 
same range. 

Changes accompanying speciation 

Clusters of Darwin's Finches differ from each other in size and shape, but 
not in plumage colour and pattern (Lack 1947, Grant 1986). The system- 
atic relationships among them are not well established. Nevertheless bio- 
chemical similarities (Yang & Patton 1981) closely parallel morphological 
similarities (Schluter 1984), and agree in defining as one cluster the 6 
species commonly known as ground finches (genus Geospiza). Within this 

P.R.Grant 102 Bull. B.O.C. 11 2A 

group, what phenotypic and genetic changes took place during speciation 
and subsequently, and can modern studies of natural selection help us to 
understand these transformations? 

First, comparisons of phenotypic data show the magnitude of the 
changes involved. Thus if ancestral G.fortis gave rise to G. magnirostris, 
without themselves undergoing any further change, then the difference 
between modern G. fortis and G. magnirostris represents the minimum 
change involved in speciation plus some fraction that occurred after- 
wards. These differences are relatively small. All coexisting species of 
ground finches differ in at least one beak dimension by at least 15% so 
another way of posing the same question is to ask how much selection is 
required to produce a shift of this size. 

Secondly, genetic data show how much evolution can be expected from 
selection of a given magnitude. The heritabilities of all G.fortis traits are 
all high, so evolutionary changes should not fall far below those caused by 
selection. Heritabilities for G. scandens traits on Daphne are generally 
lower, and those for G. conirostris traits on Genovesa are intermediate 
(Grant 1983). Heritabilities for beak depth are 0.79 for G.fortis (Boag 
1983), 0.80 for G. scandens (Price et al. 1984b) and 0.69 for G. conirostris 
(Grant 1983). 

Thirdly, measurements of natural selection provide an estimate of how 
much change can be expected in single steps. The largest values obtained, 
in the study on Daphne are 5% for selection and 4% for evolution. 

Putting these 3 quantities together yields the number of episodes of 
strongest observed selection that are sufficient to transform the beak 
depth of one species into that of another. The answer is 4. That is, 4 
episodes of selection each resulting in an evolutionary change of 4% 
would result in a net change of 1 5 % . 

Speciation and multivariate evolution 

Species are more than one dimension. The multidimensional equivalent 
to the preceding exercise requires an equation that incorporates several 
characters and their correlations. Lande's (1979) equation of multivariate 
evolution does this. A vector of phenotypic differences between 2 popu- 
lations or species in several dimensions is equated to the product, as 
before, of heritability and selection; but now heritability is a matrix of 
genetic variances and covariances, and selection is a vector of the direct 
effects of selection on each of the characters independent of the correlated 

For the ground finches, the genetic matrix is known for one species, G. 
fortis, as are the several phenotypic differences between species, and they 
can be used to calculate minimal forces of selection in terms of a vector 
length. Vector lengths are found to be small when species differ princi- 
pally in size, such as G.fortis compared with either G.fuliginosa (2.28) and 
G. magnirostris (2.76), and large when species differ in proportions, as is 
the case with G.fortis and G. scandens (15.39). 

The vector length associated with the morphological changes in G. 
fortis brought about by the drought of 1977 was 0.12. Under selection 
regimes of this sort, approximately 20 such episodes would be required to 
transform G.fortis into G. magnirostris, a much larger number than was 

Bull. B. O.C. 11 2A 103 Systematics and micro-evolution 

calculated by considering beak depth alone. Inclusion of other characters 
in the analysis is likely to increase that number. Nevertheless if one such 
episode occurred each century, the transformation of a population of G. 
fortis into G. magnirostris would take the comparatively short time of 2000 
years. In contrast, the transformation from G. fortis to G. scandens would 
take about 13,000 years. 


Measurements of the properties and performance of contemporary 
populations can be used to reconstruct past evolutionary processes. A 
knowledge of current selection regimes and heritable variation in Darwin's 
finch populations enables us to estimate the amount of selection that could 
account for differences between species. The principal results are that 
transitions between species differing largely in size could have proceeded 
rapidly, and more rapidly than for those differing in proportions owing to 
the constraining influence of genetic correlations between morphological 
traits. In reaching these conclusions I have ignored several complications 
(see Price et al. 1984b, Grant 1986, Boag & van Noordwijk 1987, Price & 
Boag 1987, Schluter 1989). These render questionable the accuracy of the 
calculations but not the overall result that selective forces are powerful 
enough to result in speciation relatively quickly. Sexual selection (Price 
1984, Lande & Kirkpatrick 1988) and drift (Grant & Grant 1992) could 
have been contributing influences. 


The task of trying to understand the evolution of a particular group of 
organisms like passerine birds is made difficult by the incompleteness of 
the group. Many species, perhaps the vast majority, have become extinct, 
and it is unlikely that we will ever know much about them. Another 
difficulty arises from the fact that species may occupy geographical ranges 
far removed from their sites of origin. For example, British bird species 
probably did not evolve, as species, in Britain. Missing species and missing 
environments make evolutionary systematics a science that works with 
partial information. 

Set against these difficulties are the successes which have been achieved 
in this and related disciplines. No class of organisms of comparable size is 
as well known systematically or biogeographically as birds. While animals 
like Drosophila are much better known genetically, the combined knowl- 
edge of ecology, behaviour, distribution, systematics and genetics of birds 
is without equal. 

What can we expect in the future, and in particular from the study of 
micro-evolution? With the human genome project underway we can look 
forward to a time in the next century when some bird species will be 
completely characterized genetically. It is technically feasible to deter- 
mine the complete architecture of avian genomes in individuals, and with 
this information to quantify precisely the variation among individuals 
within populations, between populations and between species; and it is 
feasible to determine the rates and sites at which new variants arise by 

P. R. Grant 104 Bull. B.O.C. 1 12A 

Kxpanding data banks of genetic information will permit advances to be 
made in 3 areas of relevance to this essay. First, they will permit refine- 
ments of systematic knowledge and the reconstruction of phylogeny. They 
will show in quantitative terms just how much genetic change is involved in 
speciation as well as in the evolution of higher taxa, and where in the 
genome those changes occur. Secondly, they will permit a deeper under- 
standing of development, and of the interplay between the genome and its 
environment which occurs during development; in other words, a knowl- 
edge of genetic structure will facilitate the study of function. This infor- 
mation will be essential for understanding the genetic and developmental 
constraints on, and potentialities of, evolution (e.g. see Schluter 1989). 
The diversity of passerine birds has been produced by evolution subject 
to guiding rules which are scarcely understood. We do not know how 
malleable, genetically, species are, and in what ways. 

Thirdly, they will deepen our knowledge of the genetic consequences 
of natural selection, and make more precise our understanding of the 
micro-evolutionary processes I have described in this paper. Eventually 
we may look forward to a detailed understanding of beak size and body 
size variation in genetic and environmental terms; to a knowledge of the 
number of genes involved, and to the sites, timing, mode and magnitude 
of their action. One of the reasons why micro-evolution of birds has not 
been studied more is the difficulty of capturing the adult offspring of 
known parents for heritability determination. Nevertheless there already 
exists an under-exploited potential to compare genetic characteristics of 
adults and young by molecular analysis of DNA extracted from blood 
samples from nestlings and parents. The potential will expand as genetic 
data banks expand, and intergenerational comparisons will be made in 
selected populations to determine the interplay of selection, drift and 
other evolutionary forces in bringing about evolutionary change. 

Darwin's Finches have provided a good starting point for using micro- 
evolution to interpret larger evolutionary transformations that happened 
in the past. There is both need and opportunity to increase the scope of 
such studies. The traits investigated so far are entirely morphometric, 
which is appropriate because it is these that distinguish closely-related 
members of the ground finch group of species. But many species differ in 
plumage traits and only trivially if at all in morphometric traits. Plumage 
traits are important functionally as well as systematically. They may 
evolve under sexual selection and function in species recognition. Models 
of genetic variation and measurements of selection will provide the means 
of extrapolating from micro- to macro-evolution. 


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Address: Professor Peter R. Grant, Dept. of Ecology and Evolutionary Biology, Princeton 
University, Princeton, New Jersey 08544-1003, U.S.A. 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 107 J. Haffer 

The history of species concepts and species 
limits in ornithology 

Jiirgen Haffer 

Received 15 January 1992 


Species concepts 

Morphological species concepts 
Biological species concept 
Historical 'species' concepts 
Species limits 

Ornithologists and species concepts 
Morphological species concepts 

Museum ornithologists: narrow species limits 
Explorer naturalists: wide species limits 

Old World: the Gloger-MiddendorfT school 
New World: the Bairdian school 
The pre-Darwinian species concept of Otto Kleinschmidt (1870-1954) 
Further developments 
The ascent of the biological species concept 
Population systematics 
Phyletic lineages as 'species' 
The changing number of species 


At all times during the history of modern science, ornithologists con- 
tributed to the discussion of general biological concepts based on an 
exceptionally large amount of information that scientists and collectors 
had assembled from accessible and remote parts of the world. One such 
notion is the 'species', the basic unit in the systematic hierarchy of nature. 
The seemingly endless debate about the species problem over the last 200 
years (Mayr 1957,1 982) has been fuelled and at times led by ornithologists. 
After a period of moderate stability around the middle of this century, the 
debate has gained momentum during the last 20 years. Therefore, a brief 
review of the history of the debate within ornithology would seem appro- 
priate. I restrict my discussion to the period after ornithology had 
emerged as a separate scientific discipline during the first decades of the 
19th century (Farber 1982), thus disregarding the important contri- 
butions of Ray, Linnaeus, BufTon, Kant, Cuvier and several other early 
scientists who laid the foundations of later work (Mayr 1982). 

J.Haffer 108 Bull. B.O.C. 11 2A 

During the early stages of the debate, differences of opinion regarding 
the nature of species often reflected basic attitudes toward the concept of 
evolution. After the mutability of species in space and their transform- 
ation in time through the branching of phylogenetic lineages had been 
established beyond reasonable doubt, the debate about species shifted to 
another level. In current discussions, the term species refers to several 
quite different biological phenomena of evolutionary patterns and pro- 
cesses thereby leading to continuing arguments among the proponents of 
different concepts and preventing an agreement being reached. 

In an introductory section, I present a brief overview of the various 
theoretical species concepts and of the different taxonomic species 
categories proposed. These topics have, of course, been the subject of a 
vast literature of which some titles will be mentioned below. In the main 
historical chapters, I follow several research trends in the development of 
species concepts among ornithologists and summarize several estimates 
of the changing numbers of bird species of the world. 


The species concept — the theoretical idea of the species — is a part of basic 
biological theory. During the early 19th century and before, the species 
concept was associated with theoretical ideas of typological essentialism 
and after Darwin, the species concept was part of evolutionary theory, e.g. 
the biological species concept as elaborated on by Mayr (1942, 1963). 
This species concept applies only to sexually reproducing organisms and 
it is truly valid only in nondimensional situations where species are sym- 
patic or in parapatric contact. Historical 'species' concepts of cladists 
and palaeontologists refer to phyletic lineages rather than species. 

The species as a theoretical notion (concept) needs to be distinguished 
from the species category within taxonomy to which actual species taxa 
are assigned (Mayr 1963). The taxonomic species category is, of course, 
based on the theoretical species concept, but it is a heuristic notion used to 
order the observed diversity in nature. The taxonomic species categories 
under different theoretical species concepts have been defined by differ- 
ent authors within narrow, intermediate and wide limits. The intermedi- 
ate taxonomic species category under the theoretical biospecies concept 
is Mayr's (1963) multidimensional species category. The distinction 
between the theoretical species concept and the narrow to wide species 
category in taxonomy is reflected in the title of this article on species 
concepts and species limits. The much discussed 'species problem' refers 
to (1) the application of different theoretical species concepts and (2) the 
varying methods of delimiting species taxa, i.e. their assignment to 
differently delimited species categories in taxonomy. The main species 
concepts may be briefly characterized as follows (Mayr 1942, 1963, 1969): 


Species are distinguished from other species and separated from sub- 
species (geographical 'varieties') on the basis of "degrees of morphologi- 
cal character differences" (rather than distinctness) and, in most cases, 
the fertility of conspecific individuals (rather than the isolation from non- 
conspecific populations). Ornithologists emphasizing the diversity of 

Bull.B.O.CA\2A 109 History of species concepts 

nature and applying a narrowly defined species category in taxonomy (i.e. 
circumscribing narrow species taxa) have been characterized as 'splitters'; 
others define the taxonomic species category more widely and emphasize 
the transitional nature of intergrading taxa and include wider arrays of 
geographically representative forms in more heterogeneous species taxa 
('lumpers'). We may contrast a non-evolutionary (pre-Darwinian) and an 
evolutionary (post-Darwinian) concept of morphospecies. Species were 
assumed to possess certain constant features considered as "more 
essential" under the former view and "more primitive" under the latter 

Non-evolutionary morphological concept. Under this theoretical species 
concept, the organic diversity reflects the expression of underlying 
'types' and the observed variation is the result of different manifestations 
of the 'type'. This concept is typological, creationist and basically 

Evolutionary morphological concept. Although the transformation of 
species and the branching evolution of organisms are accepted under this 
concept, species and subspecies are separated exclusively on the basis of 
morphological character differences and, in many cases, the fertility of 
conspecific individuals. Basically, this is the species concept of Charles 
Darwin in his Origin of Species (1859; not during the late 1830s) and of 
many zoologists during the late 19th into the 20th centuries. 

This theoretical concept in a sense is transitional between the typologi- 
cal and biological species concept. W. Bock (pers. comm.) pointed out 
that, ultimately, it may not be possible to make a distinction between 
authors who accept an "evolutionary morphological species concept" and 
those who accept a "biological concept" but just use morphological 
differences to recognize different species taxa or make the distinction 
between what taxa are considered species and subspecies. Even today if 
one uses the biological species concept and the fundamental criterion of 
no genetic exchange between species, species taxa are recognized almost 
entirely on the basis of morphological differences between members of 
various species. Also individual organisms are identified as members of a 
particular species on the basis of morphological similarity. Although this 
is true, I feel there is a conspicuous difference between the theoretical 
views of authors who search for intrinsic, qualitatively different morpho- 
logical characters of species (versus subspecies) and those who have the 
understanding that there is no intrinsic difference between the characters 
of species and subspecies and who just use morphological characters as 
indicators for geneflow actually or potentially to take place. 


"Species are groups of actually (or potentially) interbreeding natural 
populations that are reproductively isolated from other such groups" 
(Mayr 1942, 1963, 1969). Reproductive isolation is usually understood to 
mean genetic isolation, e.g. "possession of a shared genetic program is the 
common tie uniting individuals derived from the gene pool of a given 
species" (Mayr 1968: 164). Bock (1986) made this explicit by emending 

J. Haffer 110 Bull. B.O.C. 1 12A 

the definition to read "a species is a group of actually or potentially inter- 
breeding populations of organisms which are genetically isolated in 
nature from other such groups". This emendation appears useful in view 
of the discovery in recent decades of several cases of representative taxa, 
especially of insects, that hybridize freely along the contact zone because 
of the lack of premating isolating mechanisms, but in which such cases 
hybrids are infertile because of fully developed postmating isolating 
mechanisms (parapatric hybridization). Some birds which meet along 
"zones of overlap and hybridization" (Short 1969) may also represent 
taxa which are genetically isolated but not reproductively isolated in a 
strict sense. These biological species would be considered as conspecific 
under Paterson's (1985) "recognition concept" of species. Panov (1989) 
and Grant & Grant (1992) reviewed the complex topic of hybridization 
and introgression in bird species as it relates to ethological isolation and 
the definition of the biological species border. 

A fully differentiated biological species is a genetic unit, a reproductive 
unit and an ecological unit occupying a species-specific niche in nature 
(Mayr 1969, Bock 1986); it is capable of living sympatrically with other 
such species (synspecies — Sudhaus 1984). Taxa which replace each other 
geographically without or with only very restricted hybridization along 
the contact zone (paraspecies sensu Sudhaus 1984, as well as semispecies 
sensu Short 1969, respectively; see Table 1) are strong competitors 
owing to the lack of ecological isolation but have reached the level of 
biological species. It appears inadvisable to include ecological isolation in 
the taxonomic species definition (Mayr 1982: 273) since this would reduce 
semispecies and most paraspecies to the level of conspecific entities and 
would make the zoogeographical species (synspecies) the basic unit of the 
taxonomic system. Nevertheless, the process of microtaxonomic differ- 
entiation is not complete until genetic, reproductive, as well as ecologic 
isolation have been reached (Mayr 1942, Lack 1944, Bock 1979). 

The biological species concept is nondimensional and can be applied 
readily (directly) only to sympatric or parapatric populations. It is the 
multidimensional species notion in taxonomy with its extensions over 
space and time which applies to most real units observed in nature, the 
species taxa, and which are subject to all the difficulties of any pragmatic 
application of theoretical concepts (Mayr 1963, 1982, Bock 1979, 1986). 
The distinctiveness of species becomes increasingly vague as one pro- 
gresses geographically and chronologically further and further away from 
a single point where 2 species occur in sympatry or parapatry. The species 
category as a part of the taxonomic hierarchy should be defined broadly as 
the multidimensional species notion (many authors, however, applied 
fairly narrow limits to their taxonomic species category). Moreover, this 
category should be sufficiently broad and pragmatic to include species 
taxa of nonsexually reproducing organisms. We should also realize that it 
may well not be possible to formulate a single multidimensional species 
notion which is applicable to all known organisms. 

On continents, intergradation of contiguous populations or their 
geographical exclusion without hybridization along the contact zone 
determines their rank as subspecies and paraspecies, respectively. Allopa- 
tric populations are assigned subspecies or species status on the basis of 

Bull.B.O.C. 112A 


History of species concepts 

Figure 1. Several imaginary phylogenetic lineages to illustrate 'species' limits under the 
cladistic concept (clad.) and the palaeontological concept (pal.). Schematic representation. 
Groups of populations representing the various lineages at particular time levels (e.g. t,-t 4 ) 
are different biological species (oval circles). Vertical scale — geological time; horizontal 
scale — morphological and other biological changes. A-L represent palaeontological 
'species', except C-F, which together are one palaeontological 'species' but represent 2 
cladistic 'species'. 

inference (Mayr 1969: 197). For example, the Serin Serinus serinus and 
the Canary Serinus canaria were considered allopatric species because of 
their conspicuous differences in colour, shape of the bill and song which 
were interpreted as potential isolating factors. The Serin has invaded the 
Canary Islands in recent years, where it now lives sympatrically with 
S. canaria on several islands thus demonstrating its specific distinctive- 
ness (which, of course, it had possessed already in allopatry, although 

It may be advisable in the future to establish a scale for labelling species 
taxa by a number or a symbol according to the estimated reliability of 
their delimitation. Species taxa consisting exclusively of well differen- 
tiated allopatric subspecies or several monotypic species on islands would 
be low on this scale, whereas more widespread monotypic species on 
continents as well as polytypic species consisting of directly intergrading 
subspecies would be high on this 'reliability scale'. 

The 'horizontal' concept of the biospecies (Fig. 1) refers to genetically 
isolated reproductive communities of a particular time level such as the 
Recent period or any other time level of the geological history of the earth 
(Peters 1970, Bock 1979, 1986). The vertical extent ('thickness') of such a 
geological time 'level' ('slice') or in other words the "duration" of a species 

J. Haffer 112 Bull. B.O.C. 1 12A 

is a matter of convention and, in most cases, will be determined by the 
incompleteness of the fossil record. The term 'chronospecies' has been 
used for artificially delimited and fairly extensive portions of phylogenetic 
species lineages (e.g. Remane 1985, Willmann 1985). Anagenetic change 
of a phylogenetic lineage through time does not signify 'speciation', which 
term refers here exclusively to the phenomenon of lineage splitting. 

Morphologically differentiated taxa which merge through broad or 
narrow hybrid zones are combined as subspecies and megasubspecies of 
one biological species (Amadon & Short 1976 and in this volume). 
Admittedly, this procedure fairly frequently subsumes under one 
species name, and thus 'conceals' at that intermediate level, 2 or more 
conspicuously differentiated entities with independent biogeographical 
histories. A biogeographical species (Mayr & Short 1 970, Bock & Farrand 
1980, synspecies — Sudhaus 1984) comprises a superspecies or an inde- 
pendent biological species (which is not a member of a superspecies). 
Biogeographical species represent communities of descent and are the 
highest taxa which, on the basis of the genealogical relations and alio/ 
parapatric distribution patterns of the component forms, can be delimited 
objectively (Rensch 1934: 51, Mayr 1942: 169). 

The distribution patterns of groups of closely related parapatric bio- 
species resemble large scale mosaics composed of neatly interlocking 
patches formed by the ranges of the component species. Parapatric and 
allopatric biospecies are combined in a superspecies if they "... were once 
races of a single species but which now have achieved species status" 
(Amadon 1966, 1968). Geographically representative and closely related 
species are included in a superspecies even if their ranges overlap to a 
certain extent and the width of overlap is narrow relative to the vagility of 
taxa involved and the respective total ranges occupied (the amount of 
overlap is undefined). Component biospecies of superspecies have been 
designated paraspecies (Prigogine 1980, 1984a,b, Sudhaus 1984) if 
they are in contact, restricting the term allospecies (Amadon 1966) to 
geographically separated representatives. In some groups of animals 
parapatry probably persists long after the respective populations have 
attained genetic isolation and not only one but 2 or more speciation events 
have taken place (Haffer 1986). 

Cladistically, the representatives of a superspecies are in most cases 
each others' closest relatives because of a basically consistent association 
between character evolution, genetic-reproductive isolation and ecologi- 
cal differentiation. However, detailed analyses may reveal that this is not 
true in some cases when one of the representatives of a superspecies is the 
sister taxon of another widely sympatric species. It remains to be deter- 
mined how frequent such situations actually are. Selander (1971), 
Vuilleumier (1976) and Mayr (1980b) discussed various general aspects 
and problems of the application of the biological species concept to the 
avifaunas of the world. 

The informal term 'species group' refers to a group of closely related 
species with extensively overlapping ranges (Mayr 1963; ex-superspecies 
— Vuilleumier 1985). These species have attained reproductive-genetic 
isolation from and ecological compatibility with each other; they are fully 
biologically compatible. 

Bull. B.O.C. 1 12A 113 History of species concepts 


'Vertical' species concepts here combined under the designation 
'historical' concepts or 'phylogenetic concepts' refer to portions of a 
phylogenetic lineage in time (Fig. 1). A 'vertical' lineage, however, rep- 
resents an evolutionary phenomenon quite different from the notion of 
the 'horizontal' biological species discussed above (Bock 1979, 1986, 
Gittenberger 1972). A separate nomenclature and taxonomic system 
should be conceived to deal with phyletic lineages. The phyletic lineage is 
the continuum of a species as its members reproduce generation after 
generation through time. The phenotypic characteristics of the members 
of a phylogenetic lineage, and hence the underlying genetic bases, may 
remain the same over long geological periods (stasis) or change more or 
less gradually through time (phyletic evolution). A phyletic lineage may 
remain undivided over long periods or it may split (speciate) into 2 or more 
separate phyletic lineages from time to time (Bock 1986, Reif 1984). As 
Bock (1 986: 38) and Szalay & Bock (1991: 15) have stated "A cross-section 
of a phyletic lineage at any point in time is a species (theoretical, non- 
dimensional). However, different time slices through the same phyletic 
lineage are not different species, nor are they the same species. They are 
simply different cross-sections of the lineage at different times, with the 
earlier one being ancestral to the later one. Each time slice is a species, but 
it makes no sense to ask whether they are the same or different species; the 
question lies outside the theoretical, nondimensional species concept and 
hence, from a theoretical perspective, is a non-question." In this sense a 
species has no origin, life span or age. The species populations of a phyletic 
lineage through time often altered their morphologies drastically at differ- 
ent time levels (phyletic evolution) and their biological relations to other 
contemporary species changed completely. No species boundary can be 
meaningfully placed along such a continuous lineage undergoing a rapid 
evolutionary shift or in the case of a branching lineage. 

Of course, all phyletic lineages need to be studied in detail as they are 
important entities of the evolutionary history of a group of animals but, in 
contrast to species, they are not involved in the processes of evolution, i.e. 
phyletic evolution and speciation, which take place in living populations. 
Phyletic lineages "are the time paths (the record) resulting from the out- 
comes of these processes in species taxa. Phyletic lineages are history and 
as such are not involved in the ongoing process of evolutionary change; 
they do not have a role in the process itself. Species, not lineages, evolve 
and thereby have the proper claim to the attention of workers interested 
in the processes of evolutionary modification. Phyletic lineages have 
the proper claim for the attention of workers interested in analyzing the 
historical course of life" (Szalay & Bock 1991: 16). In their conclusion, 
these authors emphasize that "unless evolutionists and taxonomists 
make a clear distinction between these dual concepts (the species and the 
phyletic lineage), no hope exists to resolve the endless discussion on the 
ontology and epistemology of the species". The conceptual difference 
between the species of neontologists and the chrono-"species" of 
palaeontologists has been discussed by several other authors previously 
(e.g. Mayr 1942: 154, 1982: 292, Simpson 1961, Peters 1970, Bock 1979, 
Remane 1985). 

J.Haffer 114 Bull. B.O.C. 112A 

The differences between the 2 historical "species" concepts refer to 
a different delimination of "species" as portions of phyletic lineages 
(Fig. 1). I designate Simpson's (1961) concept as "palaeontological" and 
the concept of Hennig (1950, 1966) as "cladistic". The designation 
'evolutionary species' for the palaeontological concept is ambiguous, as 
this name has been applied also to certain cladistic concepts in recent 

Palaeontological "species" concept. Palaeontologists, beginning with 
Simpson (1951, 1961), defined the species as follows: "An evolutionary 
species is a lineage (an ancestral-descendant sequence of populations) 
evolving separately from others and with its own unitary evolutionary 
role and tendencies." Under this concept, species limits may or may not 
coincide with speciation events, i.e. branching of lineages. 

Cladistic "species" concept. Hennig (1966: 59) considered a species as a 
phyletic lineage between 2 successive speciation (branching) events or 
until the lineage terminates (see also Willmann 1985). Character change 
may or may not occur in the 2 daughter species. Other definitions are "A 
species is a diagnosable cluster of individuals within which there is a 
parental pattern of ancestry and descent, beyond which there is not, and 
which exhibits a pattern of phylogenetic ancestry and descent among units 
of like kind" (Eldredge & Cracraft 1980: 92) or "Species are simply the 
smallest detected samples of self-perpetuating organisms that have unique 
sets of characters" (Nelson & Platnick 1981: 12) and "A species is the 
smallest diagnosable cluster of individual organisms within which there is 
a parental pattern of ancestry and descent" ("phylogenetic species" — 
Cracraft 1983: 170). Cracraft and other cladists delimit "species" narrowly 
to be certain that these taxa are monophyletic, whereas Hennig (1966), 
Willmann (1983, 1985, 1986) and others apply the concept of monophyly 
only to groups of species. Accordingly, the latter authors delimit species 
more widely (as is done under the biospecies concept). Donoghue (1985) 
and Mishler & Brandon (1987) also proposed a "phylogenetic species 
concept" which, besides a grouping component (monophyly in the 
cladistic sense), recognizes a ranking component (e.g. interbreeding, 
selective constraints, or strong developmental canalization). This leads to 
narrow or broad delimitations of species taxa. According to most cladists, 
the life of an ancestral "species" ends when it splits into 2 new "species". 
Wiley (1981: 35), however, does permit the budding off of a "species" 
from another one which survives the speciation event. See further dis- 
cussions of cladistic "species" concepts by Frost & Hillis (1990) and by 
several authors in Cladistics 5 (1989) and 6 (1990). 


Under each of the theoretical species concepts mentioned above, 
zoologists delimited and are delimiting 'narrow' or 'wide' species taxa 
depending on the placement of the species limit at 'low' or 'high' levels of 
microtaxonomic differentiation, respectively. In other words, based on 
each theoretical species concept, systematists devised differently con- 
ceived (wide to narrow) heuristic species categories in taxonomy used to 

Bull. B.O.C. 1 1 2A 115 History of species concepts 

order the observed diversity in nature. A species limit at a fairly high level 
of differentiation results in relatively few species taxa with each species 
comprising wide arrays of variously differentiated geographical represen- 
tatives, whereas a species limit at a low level of differentiation results in 
more numerous, rather uniform, narrowly defined species taxa. 

Following Mayr (1942, 1963), Lack (1944, 1971), Short (1969, 1972), 
Bock (1 979, 1 986) and others I have schematically subdivided the process 
of microtaxonomic differentation into 6 stages (Table 1). Each of the 
intermediate levels between one fairly uniform species (stage 1) and 2 
fully biologically compatible synspecies (stage 6) are represented in the 
world's avifaunas by differentiated bird populations in contact. These 
stages are here listed in a presumed temporal sequence of gradually 
increasing microtaxonomic differentiation. Aspects of behavioural differ- 
entiation between closely related forms are subsumed under "genetic 
isolation" (e.g. differing types of song) and/or "ecological separation" 
(e.g. different feeding behaviour) and may be the cause of genetic or 
ecologic isolation between these relatives. Examples of such behavioural 
differences are many species of dabbling ducks whose reproductive iso- 
lation is maintained through different courtship behaviour and many 
species of North American warblers (Parulidae) and Holarctic tits (Parus) 
whose coexistence is maintained through different feeding behaviour and 
different feeding stations in trees. 

Table 1 is an attempt at visualizing the process of microtaxonomic 
differentiation through a schematic grid of increasing levels of morpho- 
logical, genetic-reproductive and ecological differentiation. The grid 
and, in particular, the sharp boundaries of the various stages (micro- 
taxonomic categories) are rather crude means of schematically illustrating 
the results of the differentiation process. Nature is not necessarily orderly 
and extant faunas provide many examples of taxa at transitional stages 
between the categories distinguished here or of taxa which combine 
aspects of 2 categories in different areas of contact (e.g. hybridization 
occurring in one area of contact and overlap of their ranges to some extent 
without hybridization in another area of contact). Morphological differ- 
ences may or may not render a group of populations diagnosable taxo- 
nomically at an early stage of differentiation (subspecies). In some bird 
populations genetic isolation may be completed before ecological segre- 
gation from the nearest relative is reached. This situation leads to geo- 
graphic replacement (parapatry) of these forms when they come into 
contact (with no or only limited hybridization). The frequent occurrence 
of superspecies in the avifaunas of the world (Sibley & Monroe 1990) 
indicates that ecological competition often prevents sympatry of geo- 
graphical representatives long after speciation is complete (Lack 1944, 
Mayr 1963). Many species probably perfected ecological segregation and 
certain aspects of reproductive isolation in neosympatry, but not genetic 
isolation, which must evolve fully in the initial allopatric period (Bock 
1979, 1986, Grant 1986). The process of speciation has terminated only 
after the differentiating taxa have attained genetic-reproductive and eco- 
logical separation (leading to sympatry of synspecies). Under the bio- 
species concept, most authors currently place the limit of the taxonomic 
species category at level III (Table 1), as discussed by Short (1969, 

J. Haffer 

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Bull. B.O. C. M2A 117 History of species concepts 

1972). Hennig (1966) and Willmann (1985, 1986) also delimit the species 
category at approximately this intermediate level of differentiation, 
whereas other cladists (e.g. Nelson & Platnick 1981: 12, Cracraft 1983) 
delimit the taxonomic species category at the lower levels I or II. 

Not all speciating taxa pass necessarily through all stages of the micro- 
taxonomic differentiation process (Table 1). Small founder populations 
on islands, originating presumably from few individuals and speciating in 
bottleneck situations during peripatric speciation (Mayr 1982), probably 
differentiated rather quickly and directly from low to high levels of micro- 
taxonomic modification (mode "Type lb: speciation by the founder 
effect" — Bush 1975: 346). On the other hand, many continental species 
that differentiated through 'splitting' from fairly large isolated popu- 
lations resulting from fragmentation of an ancestral species range ("Type 
la: speciation by subdivision" — Bush 1975: 341; dichopatric speciation — 
Cracraft 1984) probably originated more slowly through general genetic 
transformation (Mayr 1987: 312). Bush (1975: 341) referred to this mode 
of speciation as "a relatively long-term process". Consequently, taxa at 
various intermediate levels of microtaxonomic differentiation are com- 
paratively common in continental faunas. The separation of populations 
leading to peripatric and dichopatric speciation had been designated, 
respectively, as primary and secondary disjunctions by Hofsten (1916). 
He showed that the occurrence of these 2 different types of discontinuities 
was already well-known to Forbes, Darwin, Wallace and other early 


During the past 200 years, ornithologists have used the different species 
concepts discussed above to classify the numerous kinds of birds of the 
world. Under each theoretical species concept, systematists delimited 
species taxa within wide, intermediate or narrow boundaries, i.e. they 
assigned species taxa to differently conceived species categories within 
taxonomy. From these considerations, I have constructed Table 2 listing 
the theoretical species concepts along the horizontal axis and subdividing 
each concept along the vertical axis according to wide, intermediate and 
narrow limits of the respective species categories in taxonomy. In this 
Table, I have placed a selective number of ornithologists at a position 
approximately corresponding to their theoretical viewpoints regarding 
the species as a theoretical concept (horizontal axis) and as a category 
within taxonomy (vertical axis). Additional ornithologists are mentioned 
in the text. Certain aspects of the taxonomic species category applied by a 
systematist can be deduced from his narrow to wide delimitation of 
species taxa. On the other hand, his theoretical species notion, i.e. his 
typological-creationist or evolutionary attitude, is often far less obvious 
and more difficult to ascertain. Therefore details of the taxonomic species 
categories applied by ornithologists are treated in more detail in the 
following pages than details of their underlying theoretical species 

Schematic Table 2 and, in particular, the sharp distinction of the 
theoretical concepts do not permit an illustration of the numerous 

J. Haffer 


Bull.B.O.C. 112A 

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Bull. B.O.C.W2A 119 History of species concepts 

relations and interconnections between and among the various view- 
points which have certainly existed at all times. In addition, certain 
authors have not always been consistent in their work, applying to com- 
parable situations sometimes wide species limits and on other occasions 
intermediate species limits. Despite these difficulties, Table 2 does 
permit a valid distinction to be made between the basic theoretical views 
of such well-known authors as, e.g., Sclater, Allen, Kleinschmidt, and 

Stresemann (1927, 1951, 1975), Rensch (1929b) and Mayr (1942, 1963, 
1982) discussed many aspects of the development of ornithological sys- 
tematics in their wide-ranging studies, in particular regarding the micro- 
taxonomic levels with which I am concerned in this article. Additional 
historical data have been mentioned by Miller (1955) and Sibley (1955). 
My emphasis will be on some of those aspects not covered or only briefly 
discussed in these publications. Biographies of most ornithologists men- 
tioned below have been published by Mullens & Swann (1917), Gebhardt 
(1964 ff.), Gillispie (1970 ff.) and Means & Mearns (1988). 

I am here concerned with the discussion of the species problem by 
ornithologists. A more comprehensive treatment would need to take also 
into consideration the interesting contributions of certain botanists, 
entomologists and malacologists during the 19th century, some of which 
have been insufficiently appreciated in the recent literature. 


Nearly all zoologists of the 19th century applied morphological species 
concepts. This was the time of intensive geographical and biological 
exploration of the world. The museum specialists studied numerous 
animal collections which professional collectors had assembled abroad; 
most of these systematists placed species taxa in a narrowly defined taxo- 
nomic category of morphospecies. Several explorer-naturalists personally 
made large collections of birds, mammals and insects in the field during 
extended expeditions. They were able to apply to the study of the collected 
material their extensive field experiences and arrived at widely circum- 
scribed species taxa (broadly defined taxonomic species category). In 
addition, they analyzed various general aspects of geographical variation 
in animals. 

Museum ornithologists: narrow species limits 

The narrow Linnaean species of many 19th century ornithologists 
comprised one morphologically defined taxon (a subspecies or a mono- 
typic species in current terminology), frequently described on the basis of 
only one or two specimens which represented the 'type' of the species 
(in the sense of the Platonic typological type). Intermediate specimens 
were dismissed as hybrids possessing no more significance than any 
abnormal animal. These were the species of many museum workers in 
Europe, e.g. C. J. Temminck, L. P. Vieillot, R. P. Lesson, C. L. Brehm, 
H. Lichtenstein, N. A. Vigors, W. MacGillivray, C. L. Bonaparte, W. 
Swainson, G. R. Gray and others, during the first half of the last century 
as well as of several leading systematic ornithologists during the late 19th 
into the early 20th centuries, e.g., J. Gould, J. Verreaux, G. Hartlaub, 

J.Hqffer 120 Bull. B.O.C. 112A 

P. L. Sclater, R. B. Sharpe, E. Oustalet, H. E. Dresser, J. Cabanis, 
T. Salvadori and A. Reichenow. 

These ornithologists increased greatly our knowledge of the regional 
diversity of the avifaunas of the world but none of them seems to have 
seriously pondered the problem of distinguishing "real species from local 
varieties", i.e. distinguishing "between those characters which were 
impressed on a species at its creation, and those which may be reasonably 
attributed to external agents", a problem which Strickland (1845: 219) 
clearly posited in his well-known report on the state of ornithology. 
Geographical population differences had been mentioned in the literature 
since the time of Linnaeus, Buffon, Kant, Zimmermann, Esper, Pallas, 
and even earlier, during the 18th century (Mayr 1963, 1982, Zirnstein 

Throughout most of his life, John Gould (1804—1881) considered any 
sample of birds that differed morphologically as a morphospecies. How- 
ever, his work on Darwin's bird collection from South America and the 
Galapagos Archipelago proved decisive, because it permitted Darwin to 
appreciate the importance of the phenomenon of geographic represen- 
tation, one of the reasons for his accepting the theory of geographic 
speciation in early 1837 (Sulloway 1982a); e.g. that closely related species 
of Rhea and of Mimus replace each other on the mainland of South 
America and that most of the Galapagos landbirds, including the several 
forms of Mimus, were new species which are clearly allied to related forms 
on the South American mainland. Another crucial insight at that time was 
Darwin's realization that one could call several populations on different 
islands in the Galapagos Archipelago either varieties or species (Mayr 
1982: 409). Gould also concluded correctly that "the Galapagos finches 
were not, as Darwin had previously thought, members of widely different 
genera or even families, but rather one peculiar group of thirteen species" 
(Sulloway 1 982b: 21 ). Gould placed them in one genus and 3 closely allied 
subgenera. In later years, Gould occasionally commented on geographi- 
cal colour differences in birds of the same species, e.g. "the Tits of Central 
Europe being far brighter in colour than British specimens" and "the like 
difference exists between specimens of the same species inhabiting Van 
Diemen's Land and the continent of Australia" owing to the greater 
density and cloudiness of the atmosphere in islands, he thought (Gould 

Among the ornithologists of the late 19th century mentioned above, 
Cabanis, Reichenow, Sclater, Sharpe and Gadow did not deny the 
existence of subspecies or certain climatic varieties in nature. Sharpe and 
Gadow listed some of them in the volumes of the Catalogue of Birds in 
the British Museum which they prepared, designating these forms as 
"subspecies, a, p, y" etc. (Sharpe 1874, Gadow 1883, 1884). However, 
they and a few other authors in the 'Catalogue' series (e.g. Hargitt in 
vol. 18) assigned binomial names to these subspecies as C. L. Brehm(1823, 
1831) had done decades earlier, as well as E. Blyth (1 850) and T. C. Jerdon 
(1862). The latter 2 ornithologists recognized conspicuous geographic 
variation in many species during the course of their extensive comparative 
studies of Palaearctic and Indian birds, yet preferred in practice to give 
each race a distinct specific name. Edward Blyth had corresponded with 

Bull. B.O.C.W2A 121 History of species concepts 

Darwin during the 1850s. His discussion of the common descent of cer- 
tain bird 'species', however, refers to geographical subspecies (which 
Blyth named binomially) and therefore does not mean that he implied 
transmutation of biological species. Jerdon (1862: xxxiii) pronounced: 
"That the species were created at hap-hazard, without any reference to 
others, either of the same group, or more distant ones, is a doctrine so 
opposed to all affinities and analogies observed throughout the animal 
world, that the mind refuses to accept it, and intuitively acknowledges 
the evidence of design". The use of the term "affinity" by Jerdon is in the 
sense of Strickland and is synonymous with "homology", but not in the 
sense of affinity as we would use this term today. 

Many other museum ornithologists of the late 19th century very prob- 
ably had accepted the theory of evolution, although this is not reflected in 
their taxonomic treatment of species and they never published their views 
on this or any related topic except, e.g., Reichenow (1893), Sclater (1896: 
314) and also Alfred Newton, the doyen of British ornithologists at that 
time. He had been one of the first biologists to adopt the Darwinian theory 
of natural selection on the basis of the Darwin-Wallace articles presented 
to the Linnaean Society on 1 July and published on 20 August 1858 (Gage 
& Stearn 1988). Newton immediately applied natural selection to the 
interpretation of a phenomenon in nature, i.e. the origin of desert 
coloration in several species of larks and chats of northern Africa, and 
discussed his interpretation in a long letter written on 24 August 1858 to 
H. B. Tristram, who directly accepted this view. He presented it, with only 
a general reference to Newton, in an article which appeared in 1 859 several 
months prior to the publication of Darwin's 'Origin' (Tristram 1859: 
429-433, Cohen 1985: 590). Thus Tristram (and not Newton) became 
"the one naturalist publicly to accept and to apply the new concept of 
natural selection before the publication of the Origin" (Cohen 1985: 592; 
see also Newton 1 896: 79 and Burkhardt 1 982: 42). Most ornithologists at 
that time and into the 20th century preferred a Lamarckian interpretation 
of such phenomena. On the other hand, Newton never gave a clear defi- 
nition of what he thought a 'species' was, although it is obvious from the 
context of several discussions that he followed a morphological species 
notion. He did not include entries for 'species' or 'subspecies' in his well- 
known "A Dictionary of Birds" (1896), stating in the introduction (p. viii) 
"Nomenclature . . . owing to its contentious nature I have studied to 
avoid." Newton (1896: 343) agreed with the North American ornithol- 
ogists' abolition of a great number of what had hitherto passed as distinct 
'species', and their recognition as local forms, any 2 or more of which 
should be united under one heading. During his later years, P. L. Sclater 
(1896: 314-315) shared a similar opinion "on the vexed subjects of 
trinomials" stating that subspecies should be designated with a third 
name following the principles of the North American students of geo- 
graphical variation of birds and mammals. As examples he listed the 
trinomial names of several British and continental forms of tits. 

Many ornithologists of the late 19th century followed A. R. Wallace's 
(1858) advice: "You must consider every group of individuals presenting 
permanent characters, however slight, to constitute a species" . In discuss- 
ing the question "What is a species?", David O. Hume (1875) in India 

J.Haffer 122 Bull. B.O.C. 112A 

similarly concluded that species differ in essential (i.e. constant) charac- 
ters, however small, and not bridged over by intermediate links. Under this 
concept, all morphologically differentiated allopatric varieties, e.g. those 
inhabiting islands, were raised to the rank of separate species. 

Among North American zoologists applying a narrow morphospecies 
concept towards the end of the last century, was C. H. Merriam (1897: 
755): ". . . forms which differ only slightly should rank as subspecies even 
if known not to intergrade, while forms which differ in definite, constant 
and easily recognized characters should rank as species even if known to 
intergrade". He described no less than 78 "species" of North American 
bears (see Hall 1981, vol. 2: 952-958) and numerous "species" of prairie 
wolves (coyotes). This led to an interesting discussion on the species 
question in Science (n.s. 5, 1897), initiated by no other person than 
Theodore Roosevelt, who disagreed from a field naturalist's point of view 
with Merriam's taxonomic "oversplitting". 

Explorer-naturalists: wide species limits 

Ornithological exploration of the vast and ecologically diverse conti- 
nents of Eurasia and North America during the 18th and 19th centuries 
led to the discovery of numerous conspicuously different, but inter- 
grading geographical forms of birds and mammals which the explorer- 
naturalists combined in rather broadly circumscribed species taxa. The 
European explorers were most active during the first half of the 19th 
century, their principal reports appearing in 1811, 1833, and 1840-1867. 
Most of them worked under the influence of the typological theories of 
natural philosophy, whereas in North America systematic ornithological 
exploration began somewhat later reaching a peak during the 1870s and 
1 880s after the publication of Charles Darwin's theories of evolution. The 
European explorer-naturalists studied their collections of birds and 
mammals at different museums and some of them became museum 
specialists. Most of the North American naturalists mentioned below 
were associated with the Smithsonian Institution in Washington or with 
the American Museum of Natural History in New York. 

Old World: the Gloger-Middendorff school. 
The founder of this research tradition was P. S. Pallas, who travelled in 
Siberia and the Far East (1768-1774). He was followed by F. Faber 
(Iceland 1819-1821), J. H. Blasius (Carpathian Mountains 1835, Russia 
1840-1841), A. von Nordmann (southern Russia 1837), A. Th. von 
Middendorff (Lapland 1840, Siberia and Far East 1842-1845), L. von 
Schrenck (Far East 1854—1856), and G. Radde (eastern Siberia 
1855-1859, southern Russia 1860s-1890s). Several of these men travelled 
under the auspices of the Academy of Sciences in Petersburg to explore 
territories of the vast Russian empire. Other early explorer-naturalists in 
the services of the Academy of Sciences in Petersburg who had travelled 
in eastern Europe and Asia during the 18th century were D. G. 
Messerschmidt, G. Steller, S. G. Gmelin, and J. A. Giildenstadt. The 
results of the researches of these latter workers have been utilized and in 
part published by P. S. Pallas. Constantin Gloger (1833, 1834, 1856a,b) 
and Hermann Schlegel (1844a,b), museum workers in Berlin and Leiden 

Bull. B.O.C. 112A 123 History of species concepts 

respectively, and naturalist travellers in Europe became influential 
among the above group of explorer-naturalists through their theoretical 
reflections on the nature of species and their discussions of general aspects 
of individual and geographic variation. 

Peter Simon Pallas laid the foundations of zoological, geological, and 
geographical knowledge of vast portions of the Eurasian continent. He 
distinguished in his important 'Zoographia Rosso- Asiatica' (1811) 
between individual and geographical variation and found that numerous 
wideranging species consist of a mosaic of morphologically characterized 
climatic varieties (Stresemann 1962). His statement "Varietates nullas 
neglexi, quae in Zoologia maximi momenti certae sunt" influenced the 
work of those who succeeded him in the faunal exploration of Eurasia and 
led to their preliminary studies of the significance and cause of geographi- 
cal variation. However, based on the strongly typological view of nature 
which soon developed under the influence of German idealism and 
Naturphilosophie, Gloger, Schlegel and Blasius (as nearly all other 
European naturalists at that time) conceived species as immutable natural 
entities which had independent origins and varied geographically within 
definite limits (due to climatic or other environmental influences). 
Schlegel in Leiden (Netherlands) eventually became convinced, like C. 
L. Brehm and the entomologist H. Schaum in Germany, as well as L. 
Agassiz in North America, that also all geographical varieties had existed 
since the beginning of creation and were immutable (Stresemann 1975: 

In his study of the birds of the far northern regions, Faber (1825) 
developed the view, confirming Pallas's, that many widespread species 
have changed their appearance due to the influence of the local environ- 
ment (climatic races). C. L. Gloger's (1833: x) species definition was 
"What under natural conditions regularly pairs, always belongs to one 
species. ' ' He prepared the first comprehensive treatment of general aspects 
of the "Variation of birds under climatic influence" (1833), in particular 
with regard to plumage colour. This small book (159 pages) was originally 
prepared as the Introduction to Gloger's (1834) "Handbook" of the 
natural history of European birds when Gloger was in his twenties and 
still a student of natural sciences in Berlin (where he used the extensive 
bird collections) under H. C. Lichtenstein. The text was issued separately 
to come to the attention of a wider circle of naturalists outside the narrow 
field of ornithology. Stimulated by the observations of P. S. Pallas (the 
"excellent, well informed, true naturalist"), Gloger emphasized the 
regional intergradation of climatic varieties of birds which should not be 
separated artificially as "species". His theoretical species concept was 
typological and his taxonomic species category widely delimited. 
Gloger's observations on continuous gentle character gradients "which 
connect even the most distant extremes", anticipate the phenomenon of 
clinal character variation in current terminology. He also mentioned 
geographic variation of northwardly increasing body size, geographical 
differences of egg coloration, calls and song and even of behaviour and 
habitat preferences. Gloger (1833: 106-107) thought, however, that the 
character variation of geographical races is caused by direct influences 
of the climate and that the offspring of individuals of one variety, if 

J.Haffer 124 Bull. B.O.C. 112A 

transferred to the range of another one, would change to that plumage 
colour within a few years. He therefore proposed that climatic varieties 
not be named and existing names be placed under the synonymy of 
the species name, a suggestion which practically no later naturalist has 

Gloger (1 833, 1 834) concluded on the basis of intergradation as demon- 
strated by intermediate specimens that, e.g., Sitta caesia is conspecific 
with 5. europaea, Corvus comix with C. corone, Motacilla lugens and M. 
lugubris with M. alba, Garrulus bispecularis with G. glandarius . Many of 
Gloger's species coincide with current polytypic biospecies. In certain 
other cases, however, Gloger's 'lumping' tendency led him to combine as 
'varieties' the vicariant members of species pairs, since he had no infor- 
mation on their relationship along the contact zones: Hippolais icterinaj 
H. polyglotta, Emberiza caesia/ E. hortulana, Sturnus unicolorjS. vulgaris, 
Phoenicurus erythrogaster / P. phoenicurus and Parusmonticolus / P. major. In 
the words of a leading contemporary ornithologist, Gloger's accomplish- 
ments "have been epoch-making and, even though questioned in part by 
recent research, and partly recognized as erroneous, have been highly 
stimulating in his time" (Hartlaub 1865: 1). Gloger's pioneering contri- 
butions were little appreciated during the late 1 9th and early 20th centuries 
until Rensch (1929b) and Mayr (1942, 1982) made reference to his work 

The taxonomic philosophies of Pallas, Gloger and Schlegel were 
followed by the naturalists-explorers in their ornithological expedition 
reports: Nordmann (1840), Blasius (1844), Middendorff (1853, 1867, 
1874), Schrenck (1859, 1860) and Radde (1862, 1863, 1884), all of whom 
compared their material with samples from western and eastern Europe. 
Only Nordmann, however, accepted Gloger's suggestion not to differen- 
tiate the geographical varieties by name. The other explorer-naturalists 
beginning with Middendorff followed Schlegel (1844a,b, 1854-58), who 
had, as the first zoologist, consistently applied trinomial nomenclature to 
a fairly large number of geographical varieties (his "conspecies"), the 
name of the conspecies following the species name directly, e. g. Falco 
tinnunculus japonicus. When he worked on the material which Ph. F. 
Siebold had collected in Japan, Schlegel (1844b) simply added the geo- 
graphically descriptive term japonicus to the species name to characterize 
the morphologically deviating Japanese island population. He followed 
the same method (1844a) listing 22 geographical conspecies of European 
birds. Middendorff, Blasius and the other naturalists, however, inserted 
the expression 'var.' (varietas) between the species and subspecies name, 
as Sundevall (1840) had done in several cases before. 

The ornithologists of the Gloger-Middendorff school used the term 
variety mostly, if not exclusively, in the sense of geographical sub- 
species. Other contemporary workers did not always distinguish indi- 
vidual from geographical varieties. Therefore, the use of the term variety 
was eventually abandoned (Mayr 1963, 1982). 

Middendorff (1853) and the other naturalists had at their disposal 
many series of specimen samples representing numerous taxa from far 
distant regions of Eurasia. This material demonstrated various aspects of 
individual and geographic variation including the direct intergradation of 

Bull. B.O. C. 112A 125 History of species concepts 

many contiguous taxa of birds and mammals (bears, foxes, wolves, hares) 
in colour, measurements and form, thus revealing the conspecific nature 
of numerous narrowly conceived morphospecies of previous authors, e.g. 
the conspicuously different subspecies of such wide-ranging bird species 
as Garrulus glandarius, Motacilla alba, Pyrrhula pyrrhula, Sturnus 
vulgaris and Eremophila alpestris. Turning against one of his ornithologi- 
cal critics, Middendorff(1874: 1230) stated: "Nature appears very differ- 
ent to the travelling naturalist when he daily pursues his researches 
amidst the richest animal life, impressed by its endless shapes; and very 
different to the specialist handling a few dry skins in a museum." In a 
chapter entitled ' ' Umfang des Artbegriffes ' ' [Extent of the species notion] , 
Middendorff (1867: 790-798) stated his basic agreement with Gloger's 
broad taxonomic species category but emphasized that he doubted in 
many cases the external cause of geographic variation to lie in climatic 
influences. He dismissed Darwin's transmutation theory because by far 
the majority of the (broadly delimited) species appeared to him sharply 
separated by bridgeless gaps. He favoured a typological species notion 
and stated that transmutation may apply to only few species taxa. 

Nordmann (1840), Schrenck (1860) and Radde (1863, 1884) discussed 
similar taxonomic observations on the species which they had collected 
during their expeditions, so that several contemporary reviewers of their 
expedition reports spoke of the "Gloger school" (Homeyer 1868) or the 
"Middendorff school" (Hensel 1861). It is obvious from the publications 
of the members of these 'schools' that they considered themselves to 
be part of a research tradition. They referred frequently to the general 
discussions of Gloger and Middendorff. Radde (1884: 11) quoted the 
concepts of P. S. Pallas as the theoretical basis of his work. These 
explorer-naturalists realized at the same time that most contemporary 
ornithologists in Europe opposed their application of wide species limits 
(i.e. their broadly defined taxonomic species category). There were only 
few other taxonomists in Europe who followed Schlegel (1844a) in using, 
at least in some cases, trinomials for subspecies; e.g. Zander (1851) 
considered the various conspicuously different geographical forms of 
Motacilla alba and M.flava as conspecific and Wied (1858: 27, 101) listed 
trinomial names for 2 North American birds (Otus brachyotus americanus 
and Hirundo riparia americana) . 

Besides many taxonomic aspects of their collections, the ornithologists 
of the Gloger-Middendorff school also studied numerous general 
phenomena of geographical character variation of birds and mammals 
across Eurasia, especially the variation of body size and of the colour of 
plumage and pelage, respectively. In a lengthy chapter on 'The variation 
of Siberian animals', Middendorff (1867: 798-822) continued the 
tradition of Gloger (1833) and treated continental variation of vertebrates 
comprehensively emphasizing that body size of members of the same 
animal species increases from Africa through Europe to northeastern Asia 
(without, however, referring to Bergmann's earlier publication on this 
topic; regarding the history of Bergmann's Rule see Coleman 1979). 
Middendorff pointed out that a colourful and shiny plumage character- 
izes tropical birds, but not exclusively, as shown by the shiny portions of 
the plumage in such northern birds as Luscinia suecica, L. calliope and 

J.Haffer 126 Bull. B.O.C. 11 2A 

Somateria spectabilis. He further stated that, under the cold continental 
climate of northeastern Siberia, plumage colour turns increasingly 
whitish in many bird species and, on the other hand, becomes gradually 
more intensive and darker under the humid oceanic climate of the coastal 
lowlands both east and west of the Bering Sea, extending into humid 
Amurland, where Schrenck (1860) had made similar observations. The 
latter explorer had stressed the fact that plumage colour in birds of the 
Amur region darkens through an increase in the black, grey, blackish 
brown and grey-brown pigmentation, with or without an extension of the 
dark portions of the plumage patterns. 

The naturalists of the Middendorff school were too weak as a research 
group to constitute strong opposition to the leading, systematic ornithol- 
ogists of their times (who applied narrow taxonomic species categories). 
The members of the Gloger-MiddendorfT school remained 'outsiders' 
during the 19th century. Moreover, since they published the results of 
their ornithological studies only in costly expedition reports which had 
limited distributions, their consistent emphasis on broadly defined 
species entities of Eurasian birds and mammals, together with their 
impressive data base on geographical variation, had not the impact among 
fellow workers of the scientific community as would have been desirable. 
Probably for the same reason, the research tradition of the Gloger- 
MiddendorfT school existing during the course of over 100 years (1770s 
to 1880s and beyond) has not been widely appreciated previously by 
ornithological historians, although the significance of the early work of 
P. S. Pallas has always been stressed. 

Hermann Schlegel at Leiden and J. H. Blasius at Brunswick made great 
efforts to assemble, from the 1850s to the 1870s, series of specimens 
representing young and adult birds of the various geographical 'con- 
species' in order to determine the range of individual and geographical 
variation of a species and to analyse regional trends in the variation of 
plumage colour and body size (Baldamus 1861, F. Schlegel 1867). They 
adhered to a similar typological species concept as Gloger (1833) and 
Middendorff (1853) but assigned species taxa to a somewhat less broadly 
defined taxonomic species category. In their lists of the birds of Europe, 
both Blasius (1862) and Dubois (1871) used subspecies names routinely, 
as Schlegel (1844a,b) had done. However, Blasius and Dubois designated 
the subspecies of a species with the letters a, p, y, etc. They did not go as 
far as Gloger (and later Kleinschmidt) in 'lumping' certain geographical 
representatives into the same species; thus they circumscribed species at 
an intermediate level of microtaxonomic differentiation (Table 2). The 
list by Blasius (1862) was "privately printed" in Germany and an English 
translation issued by A. Newton. The catalogue by Dubois resembles that 
of Blasius but follows a different sequence. Both publications are scarce 
and little known. Dubois (1873) later discussed geographical variation in 
many birds, adding several subspecies to his previous list and deploring 
the application of narrow species limits by many leading systematists in 

J. H. Blasius was not an evolutionist. He stated that a bridgeless gap 
separates 2 different species, "a sharply defined boundary, free from all 
gradual transitions must occur". If the characters of geographical forms 

Bull. B.O.C. 1 1 2A 1 27 History of species concepts 

intergrade, specific separation is not justified. Environmental factors may 
cause certain geographical deviations from the type; they cannot, how- 
ever, destroy the integrity of the species. All species represent inde- 
pendent creations. An unshakeable order rules organic nature, as it also 
rules the worlds of crystals and stars (Blasius 1857: v, 1858, 1861). Most 
leading ornithologists in Germany at that time supported this typological 
and creationist, non-evolutionary viewpoint. 

Only a few ornithologists had adopted Darwinian interpretations (e.g. 
F. Kutter, G. Jaeger, W. von Reichenau; see Stresemann 1975). Among 
the latter were also Anton Reichenow in Berlin and Hans Baron (later 
Count) von Berlepsch in Hannoversch-Miinden. Reichenow had travelled 
in Central Africa during 1872/73. According to his Darwinian view "all 
extant animal species basically are varieties of older extinct forms" and 
the study of geographical variation was furnishing with inestimable 
material those naturalists who based their systematic studies upon the 
theory of evolution. At that time, Reichenow subordinated the geo- 
graphical subspecies under the species category and delimited fairly 
wide species taxa, describing numerous geographical forms from Africa 
(Reichenow 1877, 1880). Since the early 1880s, Berlepsch applied tri- 
nomial nomenclature in his studies of neotropical birds, probably 
influenced by the practice of Coues, Allen, Ridgway and other North 
American ornithologists some of whom also worked on Neotropical 
birds. Berlepsch distinguished 16, 17 and 19 trinomially named sub- 
species among 216, 177 and 289 forms, respectively, in 3 separate 
publications on birds from western South America (e.g. Berlepsch & 
Taczanowski 1883). Stimulated by the discussion of trinomial nomen- 
clature at the British Museum during the visit of E. Coues in 1884 
(Sharpe 1884, see below) and at the suggestion of G. Hartlaub, the 
German Ornithological Society, during the same year, discussed and 
agreed on the modest use of subspecies names. Based on this official 
licence, several European ornithologists continued or began to apply 
trinomial subspecies names to a modest degree (besides Reichenow, 
Berlepsch, Taczanowski and Seebolm, also several Russian workers like 
Sewerzow, Bogdanow and Menzbier). L. Taczanowski in Warsaw had 
listed mostly narrow morphospecies in his work on Southern American 
birds during the 1880s but, in his summarizing treatment of the bird 
fauna of eastern Siberia, he discussed numerous trinomially named sub- 
species (Taczanowski 1891—1893). Berlepsch was an evolutionist (like 
Reichenow) and, during the early 1890s, he lectured on the genealogical 
relationships of certain groups of birds and on various aspects 
of Darwin's theory of natural selection. (Regarding Berlepsch's and 
Reichenow's later opinions on a peculiar use of trinomial nomenclature, 
see below.) 

The contrasting views of most museum ornithologists in Europe and of 
the explorer-naturalists of the MiddendorfT group regarding narrowly 
and broadly defined taxonomic species categories, respectively, led to 
numerous controversies, particularly in Germany. Between 1826 and 
1832 (in Oken's Isis), Faber, Gloger and Bruch repeatedly attacked 
C. L. Brehm's concept of a narrow taxonomic species category and his 
use of 'subspecies' discussing various aspects of individual as against 

J. Haffer 128 Bull. B.O.C. 112A 

geographical variation which Brehm had not clearly separated. This con- 
troversy lingered on in the literature until the German Ornithological 
Society (DOG) devoted its annual meeting in 1 856 to an extensive discus- 
sion of the question "What is a species?" without solving the problem or 
reaching an agreement on the circumscription of species taxa. Temporary 
arguments flared up again after Darwin's publication of the 'Origin' 
(Stresemann 1975), but the museum specialists' view on a narrowly 
defined morphospecies category continued to dominate systematic 
ornithology in Europe and the work of the Gloger-MiddendorfT school 
fell into oblivion (hastened by an extensive unfriendly discussion of the 
ornithological work of MiddendorfT, Schrenck and Radde by a museum 
worker from the point of view of the narrow morphospecies concept — 
Homeyer 1 868-1 870). As mentioned above, few Old World ornithologists 
used subspecies names during the 1870s and 1880s until the turn of the 
century when, at the annual DOG meeting at Dresden in 1897, Hartert, 
Kleinschmidt, Berlepsch, A. B. Meyer and Wiglesworth again discussed 
the problem of subspecies and species, this time inspired by the work of 
the North American ornithologists. 

New World: the Bairdian school 

During the 1860s and 1870s, the leading ornithologists in North 
America, S. F. Baird, E. Coues, J. A. Allen and R. Ridgway, further 
developed the subspecies concept, after J. Cassin and S. F. Baird had 
named several geographical varieties of a number of species during the 
1850s (Stresemann 1975, Mayr 1982, Sterling 1988). These workers 
began to apply trinomial nomenclature to a modest degree when Baird, 
Cassin & Lawrence (1860) listed some 'varieties' of Picus villosus, 
Mniotilta varia, Tringa alpina and Bubo virginianus, those of the latter 
species even without the usual expression 'var.' in front of the subspecific 
name. Their use of trinomial names increased conspicuously during the 
1 870s (Coues 1872,1 874, Baird, Brewer & Ridgway 1 874) and during the 
1880s, e.g. Ridgway (1881), who left off the expression 'var.' in front of 
the subspecies name routinely (as had Schlegel 1844a,b in Leiden) and 
Baird, Brewer & Ridgway (1884). In 1885, certain rules on the use of 
subspecies names were adopted unanimously by the American Ornithol- 
ogists' Union and the slogan "Intergradation is the touchstone of 
trinomialism" (Stejneger 1884) became the guiding principle in North 
America (A.O.U. Code 1886, review by Allen 1890, 1908). Cutright & 
Brodhead (1981) summarized these developments, emphasizing the role 
of Elliott Coues, who was probably most responsible for the spread of 
trinomial nomenclature in North America. 

In contrast to the typological and non-evolutionary (pre-Darwinian) 
concepts of most European workers, the theoretical views of this new 
generation of North American ornithologists were fully in accord with the 
theory of evolution (though regarding the mechanism of evolutionary 
change they preferred a Lamarckian interpretation — Allen 1871, Elliot 
1892). Thus Coues (in Baird et al. 1874: 559), in a somewhat oversimpli- 
fied manner, defined the geographical variety as "a nascent species". 
The North American ornithologists defined species morphologically like 
Wallace (1858), Hume (1 875) and others had done (see above) stating that 

Bull. B.O. C. 1 1 2A 1 29 History of species concepts 

"a small amount of difference, if constant, was considered 'specific', in a 
proper sense, while a large amount of difference, if found to lessen and 
disappear when specimens from contiguous faunal areas were compared, 
was considered as not specific" (A.O.U. Code 1886, cited from Allen 
1908: 594). Many allopatric forms were raised to the rank of separate 
species, whereas others were considered as conspecific based on over- 
lapping individual variation or simply on personal judgment (Ridgway 
1901: x). 

The American ornithologists were working under the direction of S. F. 
Baird of the Smithsonian Institution (Washington), the leading vertebrate 
zoologist of mid- 19th century America and a very able scientific adminis- 
trator. Coues (1903) later designated this period the 'Bairdian Epoch' of 
North American ornithology. 

The ornithologists of the Bairdian school had arrived at the grouping of 
intergrading subspecies into widely circumscribed species taxa through 
their analyses of extensive specimen material (series of adult and young 
birds of the same species from many different locations of a species' 
range), which they had collected as physicians and naturalists of several 
transcontinental military expeditions organized by the Geological Survey 
in Washington to explore locations for railroad routes in western North 
America. These expeditions were run in an east-west direction at inter- 
vals northwards between the Mexican and Canadian borders and the 
collections sent to the National Museum at the Smithsonian Institution. 
The analyses of these collections resulted in important contributions to 
the study and interpretation of individual and geographic variation of 
birds in body size and relative size of extremities, of size and shape of bill 
and wings, and on plumage colour, including the repeated emphasis on 
the gradual, i.e. clinal, nature of geographical character variation (Baird 
1866, Allen 1871, 1875, 1876, 1877, Coues 1871, 1872, 1873, Ridgway 
1872, 1873). In discussing certain aspects of plumage colour variation, 
Ridgway (1873: 549) referred in detail to some of the results of Gloger's 
(1833) early work. 

W. Bock (pers. comm.) pointed out that the reason for the change in the 
thinking of North American ornithologists on the species concept prob- 
ably developed from the very nature of the massive surveys of the 
American West, beginning with the early railroad surveys. These surveys 
were basically practical in nature, the goal being to investigate the 
potential of the vast areas of the west in order to make decisions on future 
uses of the land, e.g. for farming, grazing, etc, and hence the need to 
collect numerous geographical samples of animals and plants, as well as to 
collect large samples from each locality. These large collections of series 
of individuals of each species from numerous geographic localities estab- 
lished the foundation for the concept of geographic variation and of the 
subspecies concept, which had its major development among the North 
American ornithologists during the second half of the 19th century. 
Whereas topography, climate and animal populations change fairly 
gradually over large distances in Eurasia, animals and plants in the 
American West with its diverse terrain and climate are subdivided into 
numerous local forms, often with reasonably strong differences between 
the local populations. Hence the very nature of the material available to 

J.Haffer 130 Bull. B.O.C. 11 2A 

the American ornithologists for study permitted them to develop the 
subspecies concept quite easily. 

There are interesting historical similarities between the coinciding 
taxonomic interpretations and the comparable application of fairly broad 
limits of morphospecies by the American ornithologists and by the earlier 
exploring ornithologists in Europe, arrived at independently by these 2 
groups, although the researchers in North America were, of course, aware 
of many European publications. For example, several European articles 
and books are referred to in the 'Introductory Remarks' of Baird et al. 
(1860); the same was the case in the opposite sense, e.g. papers by S. F. 
Baird in 1866 and by Ridgway in 1879 were reissued in German during 
the same year of publication in the Journal fur Ornithologie , where major 
ornithological books and articles were regularly and extensively reviewed; 
the same applies to Ibis in Britain. However, I did not find any evidence that 
the expedition reports of Nordmann, MiddendorfT, Schrenck and Radde 
were known in North America. The explanation for these similarities 
would seem to lie in the fact that both groups of ornithologists worked 
with ample specimen material (more extensive in the case of the North 
American workers) collected over large continental regions. Their 
analyses revealed several significant aspects of both individual and 
gradual geographical variation of bird species, and Rensch (1929b) later 
named after them certain regularities which they had discovered regard- 
ing the geographical variation of plumage colour and relative length of 
extremities (Gloger's and Allen's Rule, respectively). Although the 
North Americans were evolutionists considering species to be related to 
one another genealogically and the Europeans were creationists assuming 
an independent origin of each species, their taxonomic procedures were 
virtually identical; in other words, both groups were working under 
different theoretical species concepts but had developed comparable and 
broadly defined taxonomic species categories. 

Like Gloger (1833) 40 years earlier, Allen (1871) also on the basis of 
his Lamarckian interpretation of geographical variation, suggested not 
recognizing subspecies names; but, as in Gloger's case, this proposal was 
not accepted by other ornithologists and Allen himself soon abandoned it, 
employing subspecies names routinely in subsequent years. In view of the 
discussion which soon developed in America and in Europe regarding the 
'oversplitting' of species which vary gradually (clinally) over large regions 
(beginning with Allen 1 890), it is surprising that no other method than the 
formal description of subspecies was proposed for the analysis of geo- 
graphic variation of birds until several decades later (e.g. graphical 
mapping with the help of contour lines). The reason probably is that the 
19th century ornithologists who employed trinomial nomenclature often 
treated 'subspecies' quite typologically, almost like a morphological 
species at a lower categorical rank (Mayr 1982: 289). The attitude of their 
minds was still conditioned to a taxonomy of discrete units and variation, 
and their nomenclature was based on it. However, the collecting of large 
numbers of specimens and their study in 'series' ('suites'), beginning in 
ornithology with the naturalists of the Gloger-MiddendorfT school and 
H. Schlegel in Europe and, in particular, with Agassiz (fishes), Baird, 
Coues, Allen, Ridgway and other ornithologists in North America, 

Bull. B.O.C. 1 1 2A 131 History of species concepts 

eventually led to the overcoming of the prevailing typological view of 
variation and the development of 'population thinking', which was 
"perhaps the greatest conceptual revolution that has taken place in 
biology" (Mayr 1963: 5). 

The mission of Elliott Coues to London in July 1884 to propagate the 
application of wider species limits and the use of trinomials by European 
ornithologists failed completely. The opposition of zoologists at the 
British Museum was too strong (Sharpe 1884). Only Henry Seebohm, 
who was among Coues' audience, agreed with him. Seebohm had been 
influenced by Darwin's theories of evolution and by the work of the 
North American ornithologists. During his travels in Europe and Siberia, 
Seebohm had studied the intergradation of many so-called 'species' such 
as, e.g., Sitta caesiajS. europaea and Corvus coronejC. comix (Seebohm 
1882-1883: xi, 547, 1901: 500-504). In those years, only a few European 
ornithologists besides Seebohm (1882-1883, 1882) and Radde (1884) 
opposed the application of narrow species limits (e.g. Severzow 1873, 
Reichenow 1877, Berlepsch & Taczanowski 1883) until Victor von 
Tschusi (1890) in Austria also began to combine subspecies into wide 
morphospecies taxa following the principles of the North American 
workers, i.e. applying a truly trinomial nomenclature. On the other hand, 
a few European workers continued to designate subspecies with the old- 
fashioned expression 'var.' even into the present century (Dubois 1909, 
1912). Tschusi (1890) believed that certain species characters are con- 
stant and others like colouration and colour pattern vary within rigid 
limits which variation cannot transgress. As discussed below, Seebohm's 
theoretical ideas were later to influence the development of the biological 
species concept in Europe when E. Hartert and O. Kleinschmidt entered 
the discussion during the 1890s. 

The pre-Darwinian species concept of Otto Kleinschmidt 


In the tradition of the Gloger-MiddendorfT school as well as the work of 
H. Schlegel (1844a, b) and J. H. Blasius (1862) decades earlier (and long 
since largely forgotten*), Otto Kleinschmidt (1900, 1926) again empha- 
sized a strongly typological-creationist theoretical species concept and 
formulated a broadly defined taxonomic species category. He thus 
delimited species taxa widely, combining weakly to strongly differen- 
tiated geographical forms in one unit, a "natural species" which he called 
"Formenkreis" (array of forms). His intention was to distinguish this 
assemblage from the monotypic Linnaean species of many contemporary 
museum ornithologists in Europe and to facilitate the application of this 
method also by those workers who did not want to abandon the narrow 
meaning of the term 'species' (Mayr 1942: 112). The component forms of 
a Formenkreis represent and more or less exclude one another geographi- 
cally. Kleinschmidt gave each of his Formenkreise a new capitalized 

*Although Kleinschmidt and several other ornithologists did mention incidentally some 
papers of these early workers, the relevance of the latters' arguments regarding a broadly 
defined taxonomic species category apparently was appreciated by only a few ornithologists 
(e.g. Hartert 1901: 216) in the discussions of microtaxonomic concepts around the turn of 
the century (see also below). 

J.Haffer 132 Bull. B.O.C. 11 2A 

group name, e.g. Parus Meridionalis for the Marsh Tit (P. palustris) and 
P. Salicarius for the Willow Tit (P. montanus), to emphasize the differ- 
ence between taxa of this broadly defined new taxonomic category and the 
taxa of the narrowly defined Linnaean species category. This procedure, 
although logical, is not acceptable under the rules of nomenclature and 
was followed by practically no other systematist. 

At the beginning of this century, Kleinschmidt's efforts, together with 
those of Ernst Hartert (see below), led to the replacement of the morpho- 
logical species concept by the biological species concept in Europe, 
although Kleinschmidt's own theoretical views were basically pre- 
Darwinian and typological in nature. I emphasize, however, that most of 
the Formenkreise which he discussed in his monograph series 'Berajah' 
represent valid taxa (mostly species and superspecies) and many details of 
Kleinschmidt's methodology, such as his meticulous character analyses 
and his views on the importance of geographic representation, were 
highly influential during the first decades of this century (Stresemann 
1936: 155, Mayr 1942: 112). 

Like the workers of the Gloger-Middendorff school and the ornithol- 
ogists in North America (e.g. Allen 1871: 186-250), Kleinschmidt docu- 
mented important data on the individual and geographic variation of 
Palaearctic birds. His rediscovery of the specific distinctness of 2 
sibling species of grey tits (Parus montanus and P. palustris) led him to 
emphasize repeatedly what Lamarck in 1786 had stated in these words: 
"Two species constantly distinct in reproduction sometimes offer less 
differences between them than do two varieties of the same species" 
(Burkhardt 1987: 163); similarly Darwin: "Hence species may be good 
ones and differ scarcely in any external character" (Notebook B: 213 cited 
in Mayr 1982: 266); and also Gloger (1856a,b: 283, 301). In discussing 
Kleinschmidt's concept of the Formenkreis, Hartert (1901: 216) com- 
pared it to the species notion of C. L. Gloger, J. H. Blasius and G. Radde. 
In a similar manner, Stresemann (1936: 154) emphasized that "There is 
not the slightest difference between his 'formenkreis' and the 'species' of 
Gloger and other Pre-Darwinists". Comparable to the views of these 
earlier workers, Kleinschmidt's theoretical species concept was 
typological-creationist and his taxonomic species category (Formenkreis) 
was broadly defined. 

The typological nature of Kleinschmidt's theoretical viewpoint has 
been clearly recognized and specifically emphasized by several authors of 
the anti-Darwinian philosophical literature (Conrad-Martius 1938: 
250ff, 1949, 1952) and of the creationist literature (lilies 1983: 118). The 
basic theoretical attitude of Otto Kleinschmidt (1 870-1 954) was probably 
determined by his religious commitments as a protestant pastor, his own 
claims to the contrary notwithstanding. Eck (1990: 62) stated similarly 
that Kleinschmidt's theoretical views (with roots outside the natural 
sciences) may have been influenced by his theological convictions. Under 
the guidance of his deeply religious mother and of several protestant 
teachers, he had decided to become a pastor when he was in his teens. His 
systematic work on birds (beginning in 1892 when he was a student of 
theology) was done against the background of a deeply religious world 
view. Kleinschmidt (1900) formulated his broadly conceived taxonomic 

Bull. B.O.C. 112A 133 History of species concepts 

species category of the Formenkreis after studying, during the 1890s, 
several geographically variable species (e.g. Garrulus glandarius) , various 
sibling species ("parallel species", as he called them) in the genera Parus, 
Certhia, Regulus and the large falcons of the Falco rusticolus group. The 
Formenkreis as a taxonomic category was based on Kleinschmidt's 
typological-creationist theoretical species concept and his pre-existing 
religious attitude, through which he was sensitive to the theoretical impli- 
cations of the specific distinctness of sibling species and the general lack of 
transitional forms between any of the sharply separated species that he 
studied. The discussions of Kleinschmidt's views by several recent 
biologists (Kelm 1960, Jahn et al. 1982: 540) seem biased due to an 
emphasis of certain selected ('modern') aspects of the theoretical basis 
of Kleinschmidt's work. For this reason, and in view of the historical 
importance of Kleinschmidt's interpretations, I present my analysis of 
his views in some detail below. 

Like many pre-Darwinian systematists in Europe, Kleinschmidt 
(1900, 1926) taught that faunas are composed of "natural species", his 
Formenkreise. Each Formenkreis taxon is fairly uniform and sharply 
delimited like a crystal representing an independent unit from its 
beginning and with a separate "evolutionary" history. From his theoreti- 
cal species concept he concluded that at the core of each Formenkreis 
(hidden behind the outside appearances of colouration and form) lies its 
essence (sein Wesen — Kleinschmit 1909: 1). Only the racial characters, 
not the essential characters, vary, causing the geographical differ- 
entiation of a Formenkreis (species). Individual variation of species 
characters resembles the regular and constant swinging of a pendulum. In 
Kleinschmidt's (1926: 109) words which characterize his theoretical 
species concept: "Each Formenkreis presumably had an independent 
area of origin, an independent time of origin and an independent 
process of formation (Werdegang) with an independent rate of transfor- 
mation, in a word each had an independent world history (Weltwerden)." 
Kleinschmidt assumed that this is true even for very similar sibling 
species, e.g. Willow Tit Parus montanus and Marsh Tit P. palustris for 
which he stated (1921: 27): "And if the ancestors of Parus Salicarius and 
Parus Meridionalis once have been only two equal and microscopically 
small glass-clear droplets of protoplasma, they were two! (sic)" Even 
though Kleinschmidt assumed that the Formenkreise (species) under- 
went transformation through time and differentiated into varying 
numbers of geographical forms, the species had, in his view, no common 
history of branching evolution, each Formenkreis representing an 
independent "type". 

Based on his superb knowledge especially of Palaearctic birds and apply- 
ing the principles of his taxonomic species category of the Formenkreis, 
Kleinschmidt gathered related and geographically representative taxa in 
one Formenkreis. Due to his typological viewpoint, he placed all these taxa 
at the same low taxonomic level, designating them as subspecies tri- 
nomially despite their often drastically different taxonomic modification 
(weakly defined subspecies to vicariant species) and despite the peripheral 
range overlap of some representative forms, e.g. Pluvialis apricariaj 
P. dominica, Uria lomviajU. aalge, Picus major jP. syriacus, Luscinia 

J. Haffer 134 Bull. B.O.C. 112A 

megarhynchos/L. luscinia, Loxia pytyopsittacusfL. curvirostra/L. leucop- 
tera, Passer domesticusjP. italiaejP. hispaniolensis, and others. His broadly 
conceived taxonomic species category of the Formenkreis was, however, 
not precisely defined. In some Formenkreise, Kleinschmidt did dis- 
tinguish between main or "capital" forms and subtle forms. In current 
terminology, Kleinschmidt included in one Formenkreis a monotypic 
species or a polytypic species, several vicariant biospecies of a super- 
species or even a set of more distantly related and geographically repre- 
sentative species (e.g. the nutcrackers Nucifraga caryocatactes — N. 
columbiana, Hazel and Ruffed Grouse Tetrastes bonasia — T. sewerzowi — 
T. umbellus and the spruce grouse Dendragapus falcipennis — D. 
canadensis; see Eck 1970). Kleinschmidt's combining in one Formenkreis 
(species) even strongly differentiated and, in some cases, partially 
sympatric representatives (not very closely related biospecies) and still 
designating them trinomially as subspecies is understandable from the 
typological basis of his theoretical species concept, which led him to 
consider geographic character variation among representatives as rather 
superficial and comparatively minor, leaving the basic essence of a species 

Although many of Kleinschmidt's Formenkreise represent polytypic 
biospecies and superspecies (Eck 1990), his taxonomic procedures led to 
strong objections by many contemporary ornithologists. Possibly to 
comply with some of these objections, Kleinschmidt (1940) dis- 
tinguished, late in his life, more strongly differentiated "sectors" of a 
Formenkreis and more weakly differentiated "forms". At the same time 
(1941), he classified the Formenkreise into several different categories. 
Among German ornithological authors who followed Kleinschmidt's 
philosophy were, e.g., A. von Jordans, K. Meunier, H. Frieling and 
F. Peus. 

Under his typologically conceived theoretical species concept and the 
broad taxonomic species category of the Formenkreis, Kleinschmidt 
outlined monophyletic taxa which, however, are not differentiated at the 
same level of the taxonomic hierarchy. Therefore, the Formenkreis is not 
directly comparable with any of the evolutionary taxonomic categories 
defined under the theoretical biospecies concept (species, superspecies, 
subgenus), although it comes close to, without being identical with, the 
"zoogeographical species" (Mayr & Short 1970) which comprises inde- 
pendent biospecies and superspecies. A similar composite of variously 
differentiated geographical representatives as the Formenkreis (occasion- 
ally with overlapping distributions of the component species) is the 
" soort- complex" (species complex) as traced among various groups of 
butterflies by Toxopeus (1930). 

Further developments 

In opposition to Kleinschmidt's and Hartert's views, the German 
ornithologists Count von Berlepsch (1898, 1911) and Reichenow (1901, 
1911) abused, from the turn of the century, trinomial nomenclature in a 
very unusual manner (which was in contrast to their own previous practice 
since the 1870s). They applied trinomina to closely related geographical 
representatives, which they now, however, no longer considered as 

Bull. B.O.C. 1 1 2A 135 History of species concepts 

subspecies of a single species unit but as distinct, narrowly defined 
morphospecies ("conspecies"; not conspecies sensu Schlegel). They 
said that these separate species are similar morphologically to the 
binomially named species with which the ''conspecies" are grouped (e.g. 
they can often be identified only with the help of comparative material). 
For this reason, Berlepsch and Reichenow objected strongly when 
Hartert (1897) proposed to duplicate the species name in nominate sub- 
species (also Lorenz 1892: 17). This taxonomic procedure, of course, 
demonstrated the subordination of subspecies under the species which 
was logical under Hartert's scheme but was impossible to accept under 
Berlepsch's and Reichenow's newly established notion of "conspecies". 

During the first decades of this century, many North American orni- 
thologists continued to adhere strictly to extant morphological inter- 
gradation as a necessary requirement in relating 2 geographically 
complementary forms as subspecies (Miller 1955). Intergradation was 
understood to comprise either gradual geographical blending of inter- 
connected populations or overlapping of individual variation in geo- 
graphically separated (allopatric) populations on islands or on the 
continent (Stone 1903, 1935, Grinnell 1918, 1921). The hybridizing 
woodpeckers Colaptes auratus and C. cafer continued to be considered as 
species, and Dwight (1918, 1925: 103) believed that species taxa possess 
intrinsic qualitative characters which he assumed are fundamental and 
constant. He further stated that these characters "underlie the other vari- 
ations and determine, within specific limits, size, shape, pattern, and 
color." Species limits were drawn on the basis of morphological evidence 
and degrees of difference until Chapman (1924) suggested that each situ- 
ation should be judged biologically on its own merits, thereby dismissing 
the exclusive application of the concept of morphological intergradation. 
In his extensive and meticulous work on African birds, Admiral Lynes 
(1926: 347) followed Chapman's principles of discriminating between 
species and subspecies of birds. 

The broadly defined evolutionary-morphological taxonomic species 
category of more recent authors like Geyr (1924, 1929), Meinertzhagen 
(1928, 1951, 1954), and Eck (1985, 1988) leads to assemblages of phylo- 
genetically related and vicariant forms which exhibit geographically 
orderly (directed) character transformation throughout the continuous 
or discontinuous distributional range of these assemblages. Genetic- 
reproductive isolation of 2 taxa in contact is not a species criterion under 
this view. Such broadly conceived morphological species taxa (Table 2) 
compare with zoogeographical species (Mayr & Short 1970). Following 
Kleinschmidt (1940), Eck (1985) designated sharply differentiated 
entities within widely delimited morphological species as "sectors". 


Around the turn of the 18th and 19th centuries, several zoologists 
independently formulated definitions of the species which come quite 
close to that under the biological species concept of modern evolutionary 
biologists, although these early definitions were still conceived in a 
typological frame of mind (Mayr 1957, 1968). For example, G. Cuvier, in 
1798, concluded: "... two wild forms which live at the same place in the 

J.Haffer 136 Bull. B.O.C. 112A 

same climate, without interbreeding, and always maintain their differ- 
ences, have to be regarded as different species, no matter how trifling the 
difference might be" (Stresemann 1927, 1936). It has become known in 
recent years, that among those naturalists who conceived species biologi- 
cally was Charles Darwin. During the late 1830s, upon the return from 
his expedition, he interpreted the basic taxonomic entity as biospecies 
(Kottler 1978, Mayr 1982: 266); but, during the 1850s, he returned to a 
morphological species concept. The malacologist Adolf Schmidt (1857: 
6) stated that "forms which are repeatedly encountered living at the same 
locality without blending are to be considered as distinct species". To 
H. W. Bates (1862: 501), who explored the insect fauna of Amazonia, the 
criterion of true species was "when two or more of them are found 
coexisting in the same locality without intercrossing." Similarly, the 
entomologist Th. Eimer (1 889: 1 6) said "species are groups of individuals 
which are so modified that successful interbreeding (with other such 
groups) is no longer possible." 

Among the ornithologists of that period who fully endorsed Darwin's 
theories of evolution was Henry Seebohm in Britain who concluded 
(1882: 547): "The old definition of a species having lapsed, in conse- 
quence of the rejection of the theory of special creation, it is necessary to 
provide a new one. The first step toward an understanding of what consti- 
tutes a species is the admission of the existence of subspecies. Two forms 
which are apparently very distinct, as Corvus corone and C. comix or 
Carduelis major and C. caniceps, are nevertheless found to be only sub- 
specifically distinct — a complete series of examples from one extreme 
form to the other in each case being obtainable. These are produced by 
interbreeding." Seebohm was the first ornithologist to emphasize geo- 
graphical isolation as the sine qua non for speciation to occur and he came 
close to a biological concept of species when he stated that in geographical 
isolation, the peculiarities of two forms may "become so far separated, that 
should their areas of distribution again overlap they will nevertheless not 
interbreed, and the two species may be considered to be completely segre- 
gated" (Seebohm 1 88 1 : x) and "... species are so completely differentiated 
. . . that they may inhabit the same area without any cross-breeding 
between them" (Seebohm 1 887: 63). He also discussed geographical vari- 
ation (as opposed to individual variation) as the basis for subspecies dis- 
tinction and insisted that incipient species of birds exist in considerable 
numbers, as predicted by Darwin's theories of evolution. Seebohm 
voiced his opposition to the theoretical views of nearly all contemporary 
systematists in Britain with strong words suggesting, e.g., that they "be 
exiled to Siberia for a summer to learn to harmonise their system of 
nomenclature with the facts of nature" (Seebohm 1901: 503). 

Many ornithologists during the 19th century tacitly applied the bio- 
logical species concept in their studies of the natural history of local bird 
faunas without, however, discussing the theoretical basis of this concept. 
This was eventually done in explicit terms and with many details of its 
implications by two entomologists in Britain around the turn of the cen- 
tury, Karl Jordan (at Walter Rothschild's private museum in Tring near 
London) and Edward Poulton, the first zoologists to become fully aware 
of the biological basis for the distinctness of coexisting species (Mayr 

Bull. B.O.C. 1 1 2A 137 History of species concepts 

1955, 1982). Their work was in the tradition of Darwin's and Wallace's 
concepts of gradual evolution and speciation through the differentiation 
of geographical subspecies. The results of their analyses completely con- 
tradicted the saltationist theories of speciation of the Mendelians at that 
time (Mayr 1980a). Jordan's ornithological colleague at Tring was Ernst 
Hartert who, under the influence of the work of Henry Seebohm (1882— 
1883, 1882, 1887) and of the ornithologists in North America, had, since 
the late 1880s, delimited species broadly, applying the concept of sub- 
species and trinomial nomenclature consistently (Hartert 1891 and 
several papers on tropical birds during the 1 890s). Later on, Karl Jordan's 
influence is noticeable in Hartert's work (e.g. the subspecies definition of 
Hartert, 1903: vi, is basically that of Jordan in Rothschild & Jordan 1903: 
xlii). Hartert's contact with Kleinschmidt (Kelm 1960), in particular the 
latter's emphasis on geographical representation of allied forms, also was 
of importance. Ultimately, however, Hartert and Kleinschmidt disagreed 
over many issues which, I think, was mainly due to Kleinschmidt's typo- 
logical viewpoint. Miriam Rothschild (1983) has written a fascinating 
biography of Lord Walter Rothschild, and an informative history of the 
Tring Zoological Museum with detailed chapters on its curators E. Hartert 
and K. Jordan. They were able to base their wide-ranging studies on large 
series of local populations of birds and insects, respectively, being the first 
naturalists-systematists fully to implement the biological species concept. 
In his magnum opus on the birds of the Palaearctic fauna (1903—1922), 
Hartert presented a list of the biological species of the avifauna of this large 
area judging allopatric forms on their own biological merits without feeling 
bound to the concept of morphological intergradation as still adhered to 
by many North American ornithologists. The latter agreed, however, with 
Hartert when he united a number of European and North American bird 
'species' as conspecific, e.g. forms of Podiceps grisegena, Branta bernicla, 
Melanittafusca, Circus cyaneus, Accipiter gentilis, and others. They dis- 
agreed, however, with Hartert's inclusion of, e.g., Lanius ludovicianus in 
L. excubitor and Bomby cilia cedrorum in B. garrulus. On the other hand, 
Hartert retained species status for pairs like Corvus c. corone and C. c. 
comix as well as for Carduelis c. carduelis and C. c. caniceps because, he 
said, these forms hybridize along only narrow zones and each form main- 
tains its overall integrity and its morphologically distinct characters over 
most of its distributional range. Like most ornithologists during the late 
19th century (e.g. Allen 1871, Elliot 1892), Hartert believed geographic 
variation is caused by direct influences of the environment, an interpret- 
ation that Heinroth (1903: 103), however, dismissed pointing out that the 
pattern of plumage colour is very similar in many related species which 
inhabit totally different climatic zones. In the case of adaptive colouration 
of birds of the deserts and polar regions, Heinroth assumed its origin 
through natural selection, as Newton (letter to Tristram dated 24 August 
1858; see above), and Tristram (1859) had suggested decades earlier. 

The work of the Tring scientists ushered in the end of the widespread 
application of the concept of narrow morphospecies in Europe. The new 
theoretical viewpoint and the use of trinomial nomenclature were here 
now seen as having originated in North America. As stated above, the 
work of the Gloger-Middendorff school was largely forgotten, which is 

J.Haffer 138 Bull. B.O.C. 11 2A 

not as surprising as it may seem considering the totally different, non- 
evolutionary, theoretical attitude of the members of that 'school'. The 
leading ornithologists at the large museums, e.g. Sharpe, Sclater and 
Reichenow, continued to resist the new trend for some years and pub- 
lished quite unfavourable reviews of Hartert's work (e.g. Sclater 1904). 
However, when Hartert, Jourdain, Ticehurst & Witherby issued 'A 
Handlist of British Birds' in 1912 (in which Hartert was responsible for 
the classification and nomenclature employed) the opposition was on the 
retreat. A few years later, the B.O.U. Committee preparing 'A List of 
British Birds' (1915) had already adopted trinomials. When the last 
volume of Hartert's 'Vogel der palaarktischen Fauna' was published in 
1922, the application of his concepts of the taxonomic categories of 
species and subspecies had been generally adopted in Europe. In this 
intellectual struggle among European ornithologists of roughly 30 years 
duration, several other ornithologists had also joined forces with Hartert 
since the turn of the century, e.g. A. B. Meyer, L. Wiglesworth, C. E. 
Hellmayr, J. I. S. Whitaker and H. Schalow (Stresemann 1975). Among 
the latter, Meyer & Wiglesworth (1898) and Wiglesworth (1898) dis- 
cussed several critical aspects of individual and geographic variation in 
southeast Asian birds, proposing informal designations for populations 
representing stages in stepped or continuous character clines (as we would 
say today). These authors introduced numbers and certain symbols (> 
and < ) to designate plumage colour stages between formally named sub- 
species, of which the latter symbols have been applied by many later 

Through the increased knowledge of geographical variation of birds, 
ornithologists had by then recognized that, in some species, the repre- 
sentative forms (subspecies) can be grouped in 2 or more subspecies 
groups, e.g. forms of the Hooded Crow and of the Carrion Crow within 
Corvus corone or forms of the carduelis subspecies-group and of the 
caniceps subspecies-group of Carduelis carduelis. This led to Laubmann's 
(1921, 1932) proposal of a rather cumbersome quadrinomial nomen- 
clature which, although consistent with the hierarchical classification of 
microtaxonomic categories, did not find followers among ornithologists. 

One side effect of the arguments on theoretical questions of the species 
concept and the taxonomic species category was that ornithologists had 
become overly preoccupied with subspecies taxa and had almost lost sight 
of the species taxa themselves in regional taxonomic surveys, which 
became in reality subspecies lists. This is as true for Hartert's work 
(1 903-1 922) on Palaearctic birds, where he treated monotypic species and 
all subspecies alike (numbering them consecutively from 1 to 2300*), as it 
is for the 4th edition of the A.O.U. Check-list (1931) and for Peters' 
'Check-list of Birds of the World', which were also essentially lists of 
subspecies until Ernst Mayr assumed editorship of the Peters List with 
volume 9 (1960) and 'reintroduced', so to speak, the species as a unit 
symbolized by a binomial heading for each species taxon. 

Ludwig Plate, a professor at Jena, was among those general biologists 
who, at the beginning of this century, defended the Darwinian theories of 

•Notice Hartert's (1922 (3): vi) correction of his numbering species and subspecies from 
no. 2100 onward. 

Bull. B.O. C. 1 1 2A 139 History of species concepts 

evolution against a growing opposition. In 1914, he conceived the species 
'physiologically', stating that a species comprises all individuals which 
reproduce together sexually; a common bond between them facilitates 
mutual recognition and sexual reproduction; species taxa are real units in 
nature which exist independently of man. In North America, Taverner 
(1919) argued, in dismissing the morphospecies concept of C. H. 
Merriam, "the species is a definite entity and its essential character is its 
genetic isolation. Absence of intergradation with other forms is the only 
test of the species as it exists at present. There is a barrier that isolates 
modern specific groups one from another . . .". In the case of allopatric 
forms, "the possibility of intergradation . . . must necessarily be esti- 
mated under the guidance of what evidence we have." Also for Chapman 
(1924) "proof of distinctness of two or more forms is their occurrence 
together when breeding without intergradation." He confirmed that 
there are many species which are more similar to each other than are many 
subspecies of the same species. The taxonomic rank of geographically 
isolated taxa is to be estimated by inference, he said. 


Population systematics or the 'new systematics' steadily gained 
influence worldwide under the leadership of Stresemann, Rensch and 
Mayr during the 1920s, 1930s and 1940s. The emphasis was on the bio- 
logical species concept and on a fairly broadly defined multidimensional 
taxonomic species category. Species taxa were seen as aggregates of popu- 
lations which often vary clinally. Character gradients (clines; Huxley 
1938a,b, 1939)* of a species may run in different directions and a 'sub- 
species' may belong to more than one cline. Not even the most extreme 
splitting will lead to homogeneous 'sub-subspecies' of clinally varying 
species. Morphological, ethological, physiological, biochemical, and 
bioacoustic characters and their geographical variation were investigated 
in ever increasing detail. Phenomena studied were the population con- 
tinuum, zones of secondary intergradation, and geographical isolates. 
The publications of Rensch (1929b, 1934) and Mayr (1942) were the first 
comprehensive statements of this new research tradition which was soon 
to unify most or all systematists worldwide, including those outside the 
field of ornithology, and which, from the late 1930s through the 1940s, 
merged with population genetics and palaeontology in the synthetic 
theory of evolution (Mayr & Provine 1980). 

During the 1920s and 1930s, Erwin Stresemann contributed exten- 
sively to a clarification of the biological species concept and a meaningful 
delimitation of species taxa through his many perceptive theoretical dis- 
cussions of systematic concepts, thus building an important conceptual 
basis during the preparatory phase of the evolutionary synthesis. 
Although he was an evolutionist from the beginning of his scientific career 

*As shown in previous pages, gradual geographical variation of species had already been 
discussed briefly by Gloger ( 1 833) for Eurasian birds and, more extensively, by Allen (1871) 
and other ornithologists for North American birds as well as by Wiglesworth (1898) and 
Meyer & Wiglesworth (1898) for southeast Asian birds. Reinig (1938a) analyzed numerous 
"character progressions" in Palaearctic birds and other animals. These authors, however, 
usually intended to solve certain taxonomic problems rather than to study independent 
character clines present in species populations. 

J.Haffer 140 Bull. B.O.C. 11 2A 

in about 1910, Stresemann was influenced at first by some of the system- 
atic principles of Kleinschmidt, but soon built on the views of E. Hartert 
and L. Plate (1914). As early as 1919, Stresemann adopted a biological 
species concept as it became standard in evolutionary biology in later 
decades (Mayr 1942: 119, 1957: 17, 1980b: 96, 1982: 273): "Forms which 
have reached the species level have diverged physiologically to the extent 
that, as proven in nature, they can come together again without inter- 
breeding . . . morphological divergence is independent of physiological 
divergence" ( Stresemann 1919a: 64, 66). "Forms which can maintain 
themselves separate without interbreeding when living together under 
natural conditions are considered as distinct species" (Stresemann 1920: 
152). In the case of allopatric taxa, their rank as subspecies or species is to 
be determined by inference based upon several auxiliary criteria (degree 
of similarities in morphology, ecology, voice, etc.; overlap of the ranges of 
individual variation; comparison with comparable congeneric forms 
which are in contact and either do or do not interbreed). For several years, 
however, Stresemann continued to assign species taxa to a very broadly 
defined taxonomic category of biospecies. In 1925 and 1926, he recog- 
nized the existence of biospecies which replace each other geographically 
without or only rarely hybridizing along their contact zone. This dis- 
covery of closely related and geographically representative biological 
species (currently called allospecies and paraspecies) led Stresemann to 
accept Rensch's (1928) proposal to distinguish between polytypic species 
(Rassenkreis) and superspecies (Artenkreis) — see Haffer (1991) for further 
details. In later years, Stresemann delimited species more narrowly than 
before (see Table 2) and investigated the ecological segregation of closely 
allied biospecies (Stresemann 1943). He had interpreted the origin of 
species through allopatric speciation already in 1913 and, during sub- 
sequent years, he investigated 'mutations' as one possible mechanism of 
genetic change (Stresemann 1926). Chapman (1923, 1928) held a similar 
view but ascribed clinal character variation to direct environmental 

In contrast to this latter interpretation held by a majority of orni- 
thologists at the beginning of this century, Stresemann (1 91 9a, b,c) applied 
an historical interpretation to the phenomenon of clinal geographic 
variation. In several conspicuous subspecies pairs of European birds 
(Aegithalos caudatus, Corvus cor one, Sitta europaea, Pyrrhula pyrrhula), 
Stresemann postulated a postglacial contact of forms which had differen- 
tiated in geographical isolation during preceding glacial periods of the 
Pleistocene, leading to introgressive hybridization and to the develop- 
ment of the observed smooth geographical character gradients. This work 
was originally stimulated by Kleinschmidt's (1911) discussion of geologi- 
cal factors in the distribution of European birds (Udvardy 1992), as well 
as by the early articles of Seebohm (1 882) on interbreeding between forms 
of crows, shrikes and goldfinches, and those of Berlepsch (1885), who had 
discussed the hybridization between the eastern and western subspecies 
of the Long-tailed Tit. 

Bernhard Rensch was a student at Halle during the early 1920s, and at 
that time visited the nearby home of Otto Kleinschmidt (Rensch 1979), 
who demonstrated to him the relations of many representative forms 

Bull. B.O.C. 112A 141 History of species concepts 

on the basis of his large private collection of birds. At the same 
time, Rensch worked temporarily at the Zoological Museum in Berlin 
with E. Stresemann who, in 1925, saw to it that Rensch was employed 
by this institution (Rensch 1979: 49). Influenced by Stresemann's work 
on geographically representative biospecies, Rensch soon revised 
Kleinschmidt's terminology. In 1926, he introduced the term 
'Rassenkreis' (array of races) to replace Kleinschmidt's term ' Formenkreis' 
(Rensch 1926: 254). The latter term appeared to Rensch misleading 
because of its prior use by zoologists to designate groups of closely related 
species regardless of whether they were allopatric or sympatric. Although 
the term Formenkreis (Kleinschmidt) and Rassenkreis (Rensch) were 
indeed synonymous in Rensch's (1926) first article, at the International 
Ornithological Congress in Copenhagen (May 1926) he in fact had men- 
tioned that a Formenkreis may comprise one or several Rassenkreise 
(Rensch 1929a). In 1928, he coined the term Artenkreis (translated 
into superspecies by Mayr 1931) for a complex of 2 or more vicariant 
Rassenkreise (Rensch 1928, 1929). Since these latter publications, the 
terms Rassenkreis and Formenkreis are no longer synonyms, a fact 
overlooked by some authors until today. The 'Genus geographicum' and 
the 'geospecies' (Rensch 1931: 464) are synonyms of 'superspecies' and 
biospecies, respectively; neither of them corresponds to the term zoo- 
geographical species (Mayr & Short 1970). Rensch (1929b: 14) orig- 
inally restricted the use of the term 'species' to monotypic species taxa, 
designating polytypic species as Rassenkreise. This distinction was not 
accepted by other authors, because it became obvious that these desig- 
nations referred to different kinds of species taxa rather than to different 
taxonomic categories. The terms monotypic and polytypic species were 
introduced by Huxley (1938, 1939) independently of J. A. Allen (1910), 
who had used them quite freely in his review of the 3rd edition of the 
'Check-list of North American birds'. 

The discovery of geographically representative forms which do not or 
only rarely hybridize along their zones of contact (Fig. 2) and, therefore, 
represent biological species (Rensch 1928, 1929), eventually led to a 
reversal of the excessive 'lumping' tendency among ornithologists which 
had reached a peak in Europe under the influence of Kleinschmidt's 
views: e.g. several publications by Stresemann during the early 1920s (see 
Haffer 1991), as well as some of Hellmayr's {Catalogue of Birds of the 
Americas — 1924-1942) and Stegmann's (1934, 1935) papers on broadly 
circumscribed species. These authors used trinomial nomenclature for 
the purpose of expressing genetic relationships, also of non-intergrading 
representatives which, in some cases, exhibit different habitat preferences 
near the contact zones (see also comments by Meise 1938). The occurrence 
of vicariant biospecies with contiguous ranges, currently called parapatric 
species, demonstrated that caution must be exercised when combining as 
conspecific representative forms with adjoining or allopatric ranges. In a 
comprehensive study of the climatic rules of geographic variation and of 
population systematics, Rensch (1929b, 1934) showed that the concepts 
of polytypic species and superspecies are applicable to most groups of 
vertebrate and invertebrate animals worldwide. He abandoned his 
Lamarckian interpretation of the origin of geographical variation during 

J. Haffer 


Bull. B.O.C. 11 2A 


1. P. meyeri 

2. P. senegalus 

3. P. crassus 

4. P. flavifrons 

5. P. rufiventris 

6. P. cryptoxanthus 

7. P. rueppellii 

f . V 

— \ • • • '/ 

Figure 2. Distribution of the African parrots of the Poicephalus meyeri superspecies. Simpli- 
fied after Snow (1978). This assemblage of parapatric species was used by Rensch (1928), 
together with other evidence, to discuss the occurrence of vicariant biospecies. 

the early 1930s when be became familiar with the new redefinition of 
mutation as slight genetic variations which could respond to natural 

In North America, the systematic principles of both Hartert and 
Chapman regarding the ranking of taxa as subspecies and species were 
increasingly applied in their work by the leading ornithologists of the 
1920s and 1930s, e.g. J. Chapin, R. C. Murphy, J. L. Peters, L. Griscom 
and many others who were also influenced by the new concepts of genetics 
and evolution. Chapin (1932) warned against the hasty lumping of geo- 
graphic representatives under a binomial name to include groups that 
may have diverged to a point beyond the possibility of intergradation. He 
emphasized the genetic basis of slight subspecific differences knowing 
that "environment selects, rather than directs the variations". 

Building on the work of Stresemann and of Rensch, Mayr (1942, 1963, 
1970) prepared several major critical syntheses of the systematic, genetic 
and ecological aspects of biological species and an analysis of the 
speciation process. Thus he established the theoretical biological species 
concept in all its ramifications, based on which he defined the multi- 
dimensional species category within taxonomy. Through his contri- 
butions, the biospecies concept became one of the central tenets of the 
modern synthetic theory of evolution during the 1940s and 1950s, a fact 
too well-known to be discussed here in any detail. Lack (1944, 1949, 1971) 

Bull. B.O.C. 1 1 2A 143 History of species concepts 

added important data on the ecological aspects of the speciation process, 
as acknowledged by Mayr (1982: 274). Niche differentiation must be 
complete for 2 species to be able to occupy the same habitat. Therefore, 
several different situations may arise if species come into secondary con- 
tact (Lack 1944): (1) One species eliminates the other because it is so 
much better adapted ecologically, or (2) one species will exclude the other 
in part of its range with a narrow or broad zone of overlap developing 
where both are about equally well adapted; (3) the 2 forms will occupy 
separate but adjacent habitats in the same region of overlap; (4) both 
species are similar ecologically and occupy adjacent geographical regions 
excluding each other along the zone of contact due to ecological compe- 
tition (parapatry in current terms) or (5) both species become sympatric 
and syntopic because they are ecologically fully isolated. Lack concluded 
that ecological divergence between forms must have been initiated when 
they were isolated from each other geographically, although it may have 
been intensified after they met. 

In several historical essays, Mayr (1980a,b, 1988) discussed the role of 
systematics in the evolutionary synthesis, in particular the contributions 
made by naturalists-systematists (since about 1900) regarding the devel- 
opment of population thinking, the quantitative analysis of gradual adap- 
tive geographic variation, and the importance of geographical speciation. 
Selander (1971) critically reviewed modern studies on the systematics 
and speciation process in birds published during the 1950s and 1960s. 

In recent years, Stepanyan (1974, 1978) delimited the species of 
Palaearctic birds on the basis of a narrow species notion, often desig- 
nating entities as species that other authors consider subspecies or 
megasubspecies under the biological species concept. 


Morphological-biological changes along phyletic lineages through 
time occur slowly ('gently') or more or less abruptly. However, even 
'abrupt' shifts or changes along lineages with or without lineage splitting, 
are continuous and 'gradual', merely occurring at a higher rate than other 
lineages changes over time which occur at a slower rate (see Fig. 1). Shifts 
along lineages which may or may not be accompanied by splitting events 
(speciation) are taken by many palaeontologists to subdivide a given 
lineage into portions considered as 'species' in the time dimension. On the 
other hand, cladists subdivide lineages exclusively at splitting events 
regardless of whether considerable morphological-biological shifts have 
occurred along only one or both lineages at the time of the splitting 
event (Willmann 1 983 , 1 985). Since there is no method of subdividing the 
evolutionary continuum of phyletic lineages in a meaningful and non- 
arbitrary manner, it appears best to restrict the theoretical concept of 
species to particular time levels (whose 'duration' will have to be 
defined) and to speak of phyletic lineages in the time dimension. A 
separate taxonomy for such lineages outside the Linnaean system of 
genera and species should be designed. 

Species taxa based upon morphological analyses of fossil specimens 
may or may not correlate with reproductive communities (biological 
species). In morphologically well differentiated groups, species probably 

J. Haffer 144 Bull. B.O.C. 112A 

often refer to taxa below the level of biospecies, whereas in morphologi- 
cally (osteologically) uniform groups such as, e.g., salamanders or certain 
groups of songbirds, a fossil species probably comprises a group of closely 
allied biological species. 

In a very perceptive early remark, Neumayr (1889: 67) was insisting 
that the concept of species, as derived from observations of extant faunas, 
cannot be applied to phyletic lineages. "However", he continued, "if we 
take a particular (form) by itself without regard to the other members of 
its lineage and consider only its relations to contemporary organisms, 
then indeed this form is a good species. As soon as we take into consider- 
ation the entire phyletic lineage of which this form is a part, nothing exists 
which would correspond to a species. The species concept cannot be 
applied when reasonably complete paleontological material is available 
and must disappear from the realm of paleontology." Similarly, Simpson 
(1943: 171) stated: "Clearly a species as a subdivision of a temporal, or 
vertical, succession is quite a diffent thing from a species as a spatial, or 
horizontal, unit and cannot be defined in the same way. The difference is 
so great and, to a thoughtful paleozoologist, so obvious that it is proper to 
doubt whether such subdivisions should be called species and whether 
vertical classification should not proceed on an entirely different plan 
from the basically and historically horizontal Linnean system. So far none 
of the varied proposals for non-Linnean arrangement and nomenclature 
has been widely accepted and none seems promising at present." 

Despite this early advice (see also Sylvester-Bradley 1956, Simpson 
1961, Reif 1984) palaeontologists and cladists continue to discuss 
'species' concepts that refer to differently delimited portions of phyletic 
lineages. Hopefully, further discussions will lead to a clarification of the 
issues involved. 

An early attempt at analyzing 'vertical' genealogical relations among 
extant taxa at the level of subspecies and species was made by Reinig 
(1938a,b, 1939a,b), who wisely used a new terminology for the entities he 
delimited in his studies (contrasting them to Rensch's terms of monotypic 
and polytypic species). Considering the postglacial expansion of birds 
from postulated glacial refugia in the Holarctic Region, Reinig traced 
genealogical units ("Sippe") on the basis of his analyses of geographical 
character gradients (determining character polarity on the basis of the 
assumed direction of range expansion from the refugia). A genealogical 
unit embraces all those populations ("Kleinsippe", geographical sub- 
species) that are morphologically and geographically differentiated (diag- 
nosable) and "which are interrelated in such a way that each single group 
can be derived phylogenetically with the aid of morphological character- 
istics and historical and chorological knowledge from the group immedi- 
ately adjacent to it" in the direction of the Pleistocene refuge area, where 
the expansion of the genealogical unit presumably had started (Reinig 
1939a: 23). He felt that many species of the Palaearctic fauna may not 
represent evolutionary communities, i.e. be monophyletic in a cladistic 
sense, and explained that his term 'Sippe' (genealogical unit) has no 
definite taxonomic rank lying outside the customary categories of species 
and subspecies. Eller (1 939, 1 940) applied Reinig's methods to an analysis 
of the genealogy of geographical subspecies of the Papilio machaon group 

Bull. B.O.C. 112A 145 History of species concepts 

of butterflies. Reinig did not, however, provide examples at the species 
level to illustrate the differences between his approach and the application 
of the concept of biospecies. Non-hybridizing genealogical units in con- 
tact (paraspecies) are designated also by Reinig with a Linnaean binomen 
(species). He preferred to combine allopatric genealogical entities in 
loosely defined Formenkreise sensu Kleinschmidt. Reinig's rather unfor- 
tunate terminology of "Sippen" was 'preoccupied' by botanical usage 
and by the 19th-century natural philosopher Lorenz Oken who had 
suggested to replace the term genus by "Sippe". 

More recent analyses of the Vertical' (historical) relationships of 
groups of reptile populations at the infraspecific level are those of Bohme 
(1978) and Thorpe (1984). 

Species limits under the cladistic species concept range from fairly 
wide (Hennig 1966, Willmann 1983, 1985, 1986) to narrow (Cracraft 
1983, McKitrick & Zink 1988). Hennig and many other cladists delimit 
extant species basically following the criteria of the multidimensional 
species category. These latter systematists consider it inappropriate to 
enquire whether species are monophyletic, paraphyletic or polyphyletic, 
claiming that these terms apply only to groups of species (but see 
De Queiroz & Donoghue 1988, McKitrick & Zink 1988 and further 
discussions in Cladistics 5, 1989 and 6, 1990). On the other hand, cladists 
applying narrow species limits under the concept of the phylogenetic 
species (Cracraft 1983) assign species status to any population that is 
morphologically diagnosable (which basically renders this concept, in 
an operational, not theoretical, sense comparable to the monotypic 
morphological concept of 19th-century systematists). These cladists are 
concerned that paraphyletic and polyphyletic taxa may be ranked as 
species if medium-wide and wide species limits are applied. 

A biological species becomes paraphyletic when a daughter species 
originated through 'budding' (Fig. 3); e.g., a derivative population of a 
widespread mainland species may have reached species status on a nearby 
island. However, this speciation event had no effect on the parental bio- 
species (no. 3, Fig. 3) on the mainland from which neospecies 4 has 
budded off. The mainland species (no. 3) is real in the sense that it rep- 
resents a biological unit characterized by close genetic-reproductive and 
ecological relations among its component subspecies taxa. Traditionally, 
such biological clusters have been designated as 'species'. They would be 
in need of another categorical name if the term 'species' was to be trans- 
ferred to the lower taxonomic level of the basic component morphotaxa 
(subspecies). The cladistic analyses schematically illustrated in Fig. 3 (if 
feasible at that infraspecific level) yield relevant phylogenetic ('vertical') 
and biogeographical data on the origin of the various groups of taxa. 
However, transfer and application of the term 'species' to phylogenetic 
lineages within biospecies would confuse the issue. Cracraft (1983) and 
other cladists suggest that each of the 9 lineages illustrated in Fig. 3 
should be considered as species, regardless of their forming 4 separate 
clusters through genetic cohesion and intergradation. 

Several large sample studies of birds should be undertaken to deter- 
mine approximately what percentage of biospecies are monophyletic 
entities and how many species are paraphyletic or polyphyletic taxa. 

J.Haffer 146 Bull. B.O.C. 112A 


Figure 3. Speciation through splitting (A) and budding (B) resulting in monophyletic 
biospecies 1 and 2 (consisting of 3 and 2 subspecies, respectively) and paraphyletic biospe- 
cies 3 (3 subspecies). Species 4 which budded off from species 3 is monotypic and may 
demonstrate its species status by occurring sympatrically with some or all subspecies of 
species 3. Shading indicates genetic cohesion and intergradation of subspecies along contact 

McKitrick & Zink (1988: 8) believe that "many if not most biological 
species probably are monophyletic" and Szalay & Bock (1991: 35) are of 
the opinion that probably "many species" are paraphyletic. It would 
indeed be an important task to analyze phylogenetic lineages at intra- 
specific levels in the world's avifauna in order to understand the phylo- 
genetic relations of as many component taxa of biological species as 
possible and to study their biogeographical history. 

Geneflow among contiguous conspecific populations may prevent a 
meaningful cladistic analysis for many such taxa to be carried out. It 
would appear, therefore, that, among infraspecific entities, acceptable 
results of cladistic studies can be expected only for allopatric taxa and, in 
the case of contiguous populations, when these represent well differ- 
entiated (mega)subspecies characterized by morphological traits that can 
be assumed are not easily affected by geneflow. 


Because of the different opinions among ornithologists as to the circum- 
scription of species taxa, i.e. their application of different taxonomic 
species categories, a higher or lower number of bird species has been 
recognized at all times. These different counts refer to the birds of the 
world as a whole, of a large continental region or an archipelago, though 
not to the number of bird species at a single locality which, of course, 
coincides under the various taxonomic categories of species discussed. 
Ornithologists applying a narrow morphological species category in 
taxonomy arrived at high numbers of species which, during the last 
century, were rapidly increasing due to the continuous discovery and 
description of new forms made known through numerous scientific 
expeditions (Fig. 4). On the other hand, ornithologists following the 

Bull.B.O.C. 112A 

Number of forms 

Species and subspecies 


History of species concepts 

30,000 - 

28,500 © 


20,000 - 


species ' 

and subspecies / 


10,000 - 

G.R.Gray / 

11,162 ®' 

G.R.Gray / 

Latham **™j/ 

Brisson ' ^©^'^jys niiger 
1,500 ®-" 

V H Gh&H 


I 1 I I 

1 ! 

1750 1800 1850 1900 1950 2000 A.D. 

Figure 4. Increase of the number of species and subspecies of birds known during the last 
250 years. Application of the multidimensional species concept (under the theoretical con- 
cept of the biological species) shortly after the end of the 19th century caused a conspicuous 
decrease in the number of species taxa recognized, a development which was stopped during 
the late 1920s when geographically representative biospecies were discovered. Data are 
from Stresemann (1975), Bock & Farrand (1980) and Sibley & Monroe (1990). 

principles of the Gloger-Middendorff school in Europe and of the 
Bairdian school in North America recognized considerably fewer species; 
others arrived at an intermediate number. Whereas in North America the 
situation regarding intermediate species limits remained quite stable into 
the 20th century, a narrow monotypic species category was applied by the 
leading museum ornithologists in Europe toward the end of the 19th 
century resulting in the recognition of high numbers of species taxa, 
mainly through the influence of the authoritative 'Catalogue of the Birds 
in the British Museum' (27 volumes, 1874—1898). This trend culminated 
when R. B. Sharpe published his 'A Hand-list of the Genera and Species 
of Birds' (1 899-1 909) recognizing 1 8,939 species (many of which represent 
allospecies and subspecies). 

During the following 20 years, the situation reversed itself entirely. 
Numerous Linnaean morphospecies were reinterpreted as subspecies 
and combined in more widely conceived biological species taxa. The 
result was a precipitous decline in the number of species recognized (Fig. 
4). Several authors went too far in 'lumping' geographically representa- 
tive forms into species units. This trend was eventually halted by warning 
voices from North America (e.g. Ridgway 1924, Swarth 1931, Chapin 
1932, Stone 1935, Grinnell 1935) and especially by Rensch's (1928, 1929) 
emphasis on the existence of closely related allopatric and parapatric 
species (together forming a superspecies). A period of moderate stability 
regarding species numbers followed during the late 1930s and early 1940s 

J.Haffer 148 Bull. B.O.C. 112A 

when Mayr (1946: 68) estimated the total number of known birds to be 
8616 species. A gentle increase of species numbers began during the late 
1940s when many geographically isolated representatives were reinter- 
preted as species and combined in superspecies. This 'quiet revolution' 
(Mayr 1980b) at the microtaxonomic level during the last 30—40 years led 
to a continuous increase in the number of bird species, only slightly boosted 
by the discovery of genuine new biospecies (153 species from 1938 to 
1 985— Vuilleumier & Mayr 1 987): Bock & Farrand (1 980) counted a world 
total of 9021 species (3747 nonpasserines, 5274 passerines) and Sibley & 
Monroe (1 990) 9672 species (3960 nonpasserines, 5712 passerines). In the 
latter species list, superspecies are indicated to give a measure of ecological 
units in the world's avifauna. 


A consideration of reproductive communities (biospecies) refers to 
'horizontal' relationships of extant populations or of contemporary popu- 
lations at particular time levels in the geological past. On the other hand, 
tracing evolutionary descent of populations refers to a study of 'vertical' 
phyletic lineages (not 'species') through time. This contrasting and com- 
plementary way of looking at the 'horizontal' and 'vertical' relationships 
of taxa is reminiscent of a fundamental distinction made by several 
biologists and philosophers of the late 18th century, although details of 
these schemes are not directly comparable. 

G. L. de Buffon distinguished from after 1740 a 'real' (physical) order- 
ing of concepts and an 'abstract' ordering, thus viewing the taxonomic 
problem, in the first case, in terms of history and genealogy and, in the 
second case, in terms of morphology and character resemblance. He 
understood the different category levels — species, genera, orders, etc. — 
in 2 ways, in one as 'abstract' entities of reason, and in the other as 
grounded in the succession of real time and space in the Leibnizian 
understanding of those concepts (Sloan 1979: 117). Somewhat later, 
1775-1788, Immanuel Kant distinguished in a similar way horizontal, 
a-temporal Naturbeschreibung (description of nature) and vertical, 
temporal Naturgeschichte (history of nature). Both BufTon and Kant 
related the recognition of natural species to the historical unity of the stem 
dividing animals according to genealogy (with reference to reproduction) 
rather than on the basis of morphological character resemblance (logical 
or morphological species of Linnaean taxonomy). All animals which 
generate fertile young with each other belong to a physical species. 

Buffon's concepts, as clarified and to some extent reinterpreted by 
Kant, were made, in 1796, by Christoph Girtanner the basis of an appeal 
for a new and generalized research programme in natural history: an 
inquiry into the temporal and genealogical relations of life was to be 
separated from the traditional taxonomic and morphological approach. 
However, Girtanner's proposal had little impact on contemporary sys- 
tematic studies and the writings of influential authors. Johann 
Blumenbach during the 1790s emphasized morphological aspects (the 
habitus) and Carl Illiger in 1800 shifted ambiguously from the domain of 
Naturgeschichte to Naturbeschreibung (Sloan 1979: 143). 

Bull. B. O.C.I 12 A 1 49 History of species concepts 

My review of theoretical species concepts and of narrow to wide taxo- 
nomic species categories as applied by ornithologists over the last 200 years 
indicates that the basic questions, as in other branches of science as well, 
had been formulated already by the early pioneers (Haffer 1990). 
Throughout the 19th century, controversies persisted among ornithol- 
ogists advocating wide or narrow species limits based on interbreeding and 
morphological considerations, respectively. The 'horizontal' biological 
species concept (Mayr 1942) was accepted by a majority of systematists 
during the first half of this century. Explicitly genealogical considerations 
were introduced later by Willy Hennig (1950, 1966) in his historical 
analyses of species populations based on cladistic methods. 

Application of a narrowly defined taxonomic species category led 
systematists to assign species status to the smallest diagnosable taxa and, 
in this way, to emphasize nature's diversity at low taxonomic levels; 
whereas the delimitation of wide biogeographical species taxa (super- 
species and independent species) stresses the recognition of ecological 
units in the world's fauna (Bock & Farrand 1980). The definition of the 
biological species category takes into consideration the most significant 
microtaxonomic event, i.e. the attainment of genetic isolation by a group of 
populations; consequently, biospecies are delimited as genetically closed 
reproductive communities at intermediate levels of microtaxonomic 

A practical application of a narrow, morphologically defined taxonomic 
species category (e.g. the cladistic concept of 'phylogenetic species') 
would result in an enormously increased number of taxonomic species 
compared to that currently recognized under the multidimensional taxo- 
nomic species category. On the other hand, application of the category of 
the wide biogeographical species would lead to a reduction of the number 
of presently recognized species. The approximately 9600 known extant 
biological species of birds (Sibley & Monroe 1990), according to 2 esti- 
mates, form 5000-6000 biogeographical species (Bock & Farrand 1980) or 
7000 + 200 biogeographical species (Mayr 1980b). These current issues 
in systematic ornithology represent the latest reformulation of ancient 
questions which have been discussed intensively throughout the nine- 
teenth century and before. 

All levels of differentiation at which species limits have been proposed 
are biologically significant. It will be advisable, therefore, that these stages 
of increased microtaxonomic differentiation are taken into consideration 
by identifying and listing the subspecies groups (megasubspecies, i.e. 
'phylogenetic species'), the biological species and the biogeographical 
species in the world's avifaunas. In this way, the conceptual relations 
among these taxonomic categories and their component taxa may be 
studied, and the various entities may be used in analyses of the biogeo- 
graphical and phylogenetic history as well as the ecological divergence of 
genera and families of birds. 


I am very grateful to Ernst Mayr (Cambridge, Massachusetts) for information on several 
points discussed in this article and for his critical review of this manuscript. W. J. Bock (New 
York) discussed with me the theory of species concepts; I gratefully acknowledge his 
detailed review of this manuscript and his important suggestions for improvement. S. Eck 

J.Haffer 150 Bull. B.O.C. 112A 

(Dresden), H. Pieper (Kiel) and the late H. E. Wolters also read a first draft and suggested 
various useful amendments. In Bonn, I thank R. van den Elzen, K. Schuchmann, G. 
Rheinwald, C. Naumann, W. Bohme and C. Hauser for occasional discussions and for their 
permission to use the collections and libraries of the Alexander Koenig Museum at any time. 
The following persons kindly supported my work by providing various information, loan of 
publications and access to their personal or institutional libraries: E. Bezzel (Garmisch- 
Partenkirchen), H. Englander (Koln), the late H. Kelm, A. Kleinschmidt (Wolfenbiittel), 
M. Louette (Tervuren), G. Mauersberger (Berlin), J. Neumann (Neubrandenburg), D. S. 
Peters (Frankfurt), W.-D. Reif (Tubingen), H. Ringleben (Bremen), R. Schlenker 
(Radolfzell,) and B. Stephan (Berlin). 

The theoretical concept of the biological species and the multidimensional species category, 
as currently applied by a majority of ornithologists and by many other biologists, replaced 
the typological-morphological species concept during the first half of this century and 
became a central tenet of the synthetic theory of evolution. The concept of biospecies is a 
'horizontal' concept referring to contemporary reproductive communities at any particular 
period, e.g. the Recent period or any other time level of the geological past. Historical 
'species' concepts as applied by cladists and palaeontologists refer to artificially delimited 
portions of 'vertical' phyletic lineages for which the application of the term 'species' causes 
severe problems. Discussions would be simplified if the concept and term 'species' was to be 
restricted to cross sections of phyletic lineages at any time level and a separate taxonomy 
outside the Linnaean system of genera and species was to be conceived to deal with phyletic 
lineages. Under each of the theoretical species concepts, species taxa are assigned broadly to 
intermediate or narrowly defined taxonomic species categories. 

Ornithologists of the 19th century applied morphological species concepts, emphasizing 
morphological character differences between species (rather than distinctness) and the fer- 
tility of conspecific individuals (rather than the isolation from non-conspecific populations). 
Nearly all leading museum ornithologists in 19th-century Europe delineated monotypic 
Linnaean species, whereas the explorer-naturalists of the Gloger-Middendorff school 
(including Pallas, Faber, Gloger, Nordmann, MiddendorfT, Schrenck, Radde, as well as 
Schlegel and Blasius) delimited widely circumscribed species taxa. Their researches in the 
vast territories of eastern Europe, Siberia and the Far East from the late 18th century to the 
1880s and, in particular, their rich specimen material, demonstrated direct intergradation 
of many taxa (geographical varieties) of birds, thus revealing the conspecific nature of 
numerous narrowly conceived morphospecies previously described by museum workers. 
The ornithologists of the Gloger-Middendorff school also studied several conspicuous 
phenomena of geographical character variation in birds (and mammals) across Eurasia, 
especially plumage colouration (and pelage) and body size, but none of them was an evol- 
utionist. They all adhered to a typological-creationist theoretical species concept. During 
the late 19th century, the museum specialists' taxonomic notion of narrow morphospecies 
dominated systematic ornithology in Europe, overtaking the work of the naturalists of the 
Gloger-Middendorff school, which fell into oblivion. 

The ornithologists of the Bairdian school in North America (Baird, Coues, Allen, 
Ridgway) further developed the concept of subspecies after the 1850s and especially from 
the 1870s onward. Their views were fully in accord with Darwin's theories of evolution; 
thus they defined the subspecies in a somewhat simplified manner as 'nascent species'. 
These ornithologists were able to base their studies on collections of extensive specimen 
material which they had obtained during a series of exploring expeditions across the North 
American continent. Their studies led to the discovery of many aspects of both individual 
and geographic variation in birds. 

There are interesting historical similarities between the coinciding taxonomic inter- 
pretations and the comparable application of fairly broad limits of morphospecies by the 
North American ornithologists and the earlier exploring ornithologists in Europe, arrived 
at independently by these research groups. The study of specimens in 'series' ('suites'), 
beginning with the naturalists of the Gloger-Middendorff school and, in particular, with the 
naturalists of the Bairdian school in North America, eventually led to the overcoming of the 
prevailing typological view of variation and the development of 'population thinking'. 

Influenced by the work of Henry Seebohm in Britain and that of the North American 
ornithologists, Hartert in England and Kleinschmidt in Germany jointly succeeded in 
overcoming the strong opposition of the leading ornithologists in Europe during the 1890s 
and early 1900s and introduced a concept which soon developed into the biological species 
concept through the work of Stresemann, Rensch, and in particular, Ernst Mayr. 

Bull. B. O.C. 11 2 A 151 History of species concepts 

Hopefully, ornithologists will continue the study of taxa at low, intermediate and 
high levels of microtaxonomic differentiation and will identify the subspecies groups, bio- 
logical species and the biogeographical species in the world's avifaunas. Cladistic analyses 
will provide historical ('vertical') overviews of phyletic lineages at different taxonomic 


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© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 112A 159 J.Jacob 

Systematics and the analysis of integumental 
lipids: the uropygial gland 

by J. Jacob 

Received 13 March 1992 

Whilst classification of birds has been exclusively deduced from anatom- 
ical, morphological and ethological criteria up to the middle of this 
century, more recently it became obvious that chemical data also may be 
used to study the relationships between species. Since DNA codes for all 
genetically dependent properties, its precise analysis could give us the best 
answer to questions on classification. Attempts have been made accord- 
ingly to use DNA analysis for this purpose, although the method suffers 
from the fact that no definite structures can presently be obtained, since 
only the extent of more or less identical sequences may be calculated from 
the data generated. Nevertheless, Sibley and co-workers have suggested 
an avian system based upon the so-called DNA/DNA-hybridization 
experiments (Sibley & Ahlquist 1990). 

Since DNA, of course, generally codes for the entire chemistry coursing 
in the organism which depends on the enzymatic equipment, the analysis of 
the enzymatic activities being responsible for these processes could also be 
used for chemotaxonomic attempts (protein patterning). Before DNA hy- 
bridization techniques became available, protein patterning had been used in 
this way by various authors (e.g. Sibley 1970, Sibley & Ahlquist 1972). 

Proteins are the final determinant of the formation of the various endogen- 
ous as well as the externally released secretions. These secondary metabolites 
also reflect the enzyme equipment of organisms to a certain extent, although 
chemotaxonomists using this method must be aware that they are looking 
through a necessarily small window into the complex reality of life. 

The pattern of the lipid constituents formed in the uropygial gland 
(preen gland) of birds has been found to be very characteristic for a species 
and fortunately differs markedly between various taxa (Jacob 1978, Jacob 
& Ziswiler 1982). This has led to a broader investigation of these lipids 
which may contribute to our understanding of relationships among avian 
species. Some of these results along with some hitherto unpublished data 
are reviewed here. 

It has been found that preen gland secretions, being the main sources of 
avian integumental lipids in most instances, consist of monoester waxes, 
which are composed of a fatty acid and a monohydric alcoholic moiety. 
The structure may be condensed to the formula: 

with R and R' standing for an alkyl chain — C n H 

2n + 

J. Jacob 160 Bull.B.O.C. 11 2A 

Only few exceptions to this finding have been reported. For instance, in 
galliform and apterygiform species diols have been found instead of 
monohydric alcohols. Occasionally also, fatty acids may be replaced 
by hydroxy acids, as found e.g. in the case of pigeons and in some 
Ciconiiform species (Ciconia ciconia — Jacob 1976, C. nigra — Jacob, 

Uropygial lipids in systematics 

Meanwhile some 500 different species have been analyzed for the 
chemical composition of their uropygial lipids and a broad structural 
variety of the above waxes has been detected. Both of the wax moieties 
may vary in 4 respects: 

(1) variation of the chain length; i.e. 'n' in the above — C n H 2n+1 may 
stand for odd and even numbers from about 6 up to 30; 

(2) variation of the location of the substituent; i.e. substituents may be 
located at various carbon atoms. Biochemically there are more basic 
differences between 2 waxes, one being branched at even and the 
other at odd carbon atoms compared to 2 waxes both branched at 2 
different but even carbon atoms; 

(3) variation of the degree of substitution; i.e. R and R' may be more or less 
alkyl-branched resulting in mono, di-, tri-, tetra- or even penta- 
methyl-branched acidic and/or alcoholic moieties (e.g. in Alcedo 

(4) variation of the substituent; i.e. the substituent may be a methyl- 
( — CH 3 ), an ethyl- ( — C 2 H 5 ), a propyl- ( — C 3 H 7 ) or a butyl-group 
(-C 4 H 9 ). 

As an example, monoester waxes composed of 3 -methyl-substituted fatty 
acids and 3-methyalkanols have been found as main constituents of the 
preen wax from finches (Fringillidae), whereas 2-ethyl-substituted fatty 
acids and unbranched alcohols are structural elements in the case of wrens 
(Troglodytidae) (Fig. 1.) 

(3) (2) (1) (1) (2) (3) 

CH 3 — (CHA — CH — CHz — C — O — CHa — C\\ — CH — <CH 2 ) m — CH 3 

CH 3 O CH 3 


(2) (1) 
CH 3 — (CH 2 ) n — CH— C— O— (CH 2 ) m — CH 3 


QjHs O 

n and m ■ odd- or even-numbered 

Figure 1 . Examples of different structures of monoester waxes found in finches and in 

Because of the obviously unlimited combination of these structural 
moieties, an immense number of different final structures may be 
expected, most if not all of which are actually realized in nature. From this 
it would not be surprising if each bird had its own specific wax pattern. 

Bull.B.O.C. 112A 


Integumental (uropygial) lipids 



J00% Dimethyl 

100% Trimethyl 

2,6,10- trimefhyl-subsf. 

Figure 2. Intraspecific variation of the quantitative composition of wax acids from the 
uropygial gland secretion of the Blackbird Turdus merula (n = 18). 

As we know now, however, this is definitely not the case. Prior to chemo- 
taxonomic considerations, the intraspecific variation of the lipid compo- 
sition has to be checked. This has been done for a number of species and 
the variation is found to be very limited, as may be seen from Fig. 2, with 
Turdus merula as as example. The circle surrounding the cloud of single 
points in this figure may be taken as a measure of the degree of intra- 
specific variation and it is the size of this cloud which decides whether 2 
species can be separated by this method. Individuals of a species and its 
subspecies or races cannot be distinguished from each other by this 
method. Within different genera, only quantitative differences are found, 
which in many cases, however, are not significant and hence often cannot 
be used for classification. Qualitative structural differences may be 
expected at the family level, where at least quantitatively different pat- 
terns are observed. Orders may be distinguished by their qualitatively 
different patterns. 

In Table 1 the specific characters for a number of orders are 
summarized. These data not only allow distinction between orders, but 
also seem to indicate relationships between some of them. For instance, it 
appears reasonable to assume that kiwis (Struthioniformes), tinamous 
(Tinamiformes) and galliform birds (Galliformes) form a group of related 
orders on the basis of the occurrence of alkane-2,3-diols in all of them. 
Similarly, Phoenicopteriformes and Anseriformes have many typical 

J. Jacob 


Bull.B.O.C. 11 2A 


Typical structural characters found in the uropygial gland waxes in species from different 

Orders of birds 




















complex mixture of 2-; 3-; 4-; 
2,x-; 3,x-; 4,x-; 2,x,y-; 3,x,y- 
methyl-substituted acids 

similar to the Sphenisciformes 

unbranched and 3-hydroxy 


3-; 2,x-; 3,x-; 2,x,y-; 3,x,y-; 
2,x,y,z-; 3,x,y,z-methyl- 
substituted as well as 2-ethyl-; 
2-ethyl-x-methyl- and 2-ethyl- 

heterogenous, varying 
significantly between families 

2,6-; 4,6-; 2,x,y-methyl- 


unbranched, 2-; 4-; 2,x-; 4,x-; 

2,x,y-; 2,x,y,z-methyl- 


2-; 2,x-; 2,x,y-methyl- 

substituted with the last sub- 

stituent near the end of the 


2-; 4-; 2,x-; 4,x; 2,x,y; 4,x,y; 

2,x,y,z- and 4,x,y,z-methyl- 

substituted with substituents 

located at every 4th carbon 


2-; 4-; 2,x-; 4,x-; 2,x,y-methyl- 



unbranched and 3-hydroxy 

unbranched, 2-, (w-1)- and 
mainly 3-methyl-substituted 

2-ethyl, 2-propyl- and 


3-; 3,x-methyl-substituted 

heterogenous, varying 
significantly at the family level 

2,x,y-; 3,x,y-; 4,x,y, -methyl- 

similar to the Sphenisciformes 

unbranched alkanols and 

unbranched alkanols and 

unbranched, 2-; 4-; 2,x-; 4,x-; 
2,x,y-; 4,x,y-; 2,x,y,z-methyl- 

see acids 


unbranched; monomethyl- 
substituted at even-numbered 
carbon atoms 

unbranched; monomethyl- 
substituted at even-numbered 
carbon atoms 

mainly unsubstituted, other- 
wise monomethyl-substituted 
at even-numbered carbon 

mainly unsubstituted, other- 
wise monomethyl-substituted 
at even-numbered carbon 


mainly unsubstituted 

mainly 3-methyl-substituted 

unbranched and monoethyl- 
substituted at even-numbered 
carbon atoms 
unbranched; 2- and 2,x- 
unbranched and 3-methyl- 
see acids 

Bull. B.O.C. 112A 163 Integumental (uropygial) lipids 

constituents in common, and this holds also for the Sphenisciformes and 
the Procellariiformes. 

Two examples may be given for the contribution of preen wax analysis 
to systematic questions: (1) the separation of the Tytonidae (barn owls) 
from the Strigiformes (owls) and (2) the systematic position of Vultur 
gryphus (the Condor). 

Separation of the Tytonidae from the Strigidae 

The chemical composition of the uropygial gland waxes of various 
owls (Jacob & Poltz 1974, Jacob & Hoerschelmann 1984) indicates that 
Strigiformes are characterized by the occurrence of 2-alkyl-substituted 
fatty acids with an ethyl-, propyl- and/or a butyl substituent, all very 
rare compounds, hardly any of which have been found anywhere else 
in nature. The alcoholic moiety is composed of unbranched and 
monomethyl-branched alkanols with a methyl substituent located at an 
even carbon atom. However, Tyto possesses an entirely different wax 
pattern composed of 3-methyl- and 3,x-dimethyl-substituted fatty acids 
and 3-, 3,x-, 4, and 4,x-methyl-substituted alcohols. Hence, Tytonidae 
may be readily distinguished from Strigidae by basic differences in their 
preen wax composition, as can be seen from Fig. 3. The barn owls (if they 
are owls at all) seem to link the owls with some other Orders such as 
Piciformes, Cuculiformes and Apodiformes, in which identical or at least 
very similar structures have been detected. 

Strigidae .. 

CH 3 — (CHaJn — CH — C — O — (CH 2 ) a — CH — (CH 2 ) b — CH 3 
I I 


R = -C 2 H 5 ; -C 3 H 7 ; or -C4H9 

R' = -CH 3 or -H 

a and b odd-numbered 

n = odd- or even-numbered 

Tytonidae O 

CH 3 — (CH 2 ) n — CH— CH 2 — C— O— (CH 2 ) a — CH— (CH 2 ) m — CH 3 

I I 

CH 3 CH 3 

Figure 3. Chemical structures found in the preen waxes of Strigidae and Tytonidae. 

The systematic position of the Condor Vultur gryphus 
A nice example for an interdisciplinary approach to the solution of 
systematic problems has recently been given by comparing biochemical 
and ethological findings in the case of the Condor Vultur gryphus 
(Cathartidae). Although Beddard (1898) found similarities between 
Cathartidae and Ciconiiformes nearly 100 years ago, other biologists have 
generally associated Vultur with the birds of prey rather than with the 
Ciconiiform birds. Konig (1982) found support for Beddard's statement 
by studying the mating behaviour; and as presented in Figure 4, a com- 
parative analysis of the preen wax composition of the Condor, storks and 
birds of prey clearly shows that identical wax patterns are synthesized in 
storks and in the Condor (Jacob 1983). These findings have now also been 
confirmed by DNA/DNA-hybridization experiments (Sibley & Ahlquist 

J. Jacob 164 Bull.B.O.C. 112A 

Ciconia (e.g.: Ciconia ciconia, Ciconia nigra, 
Xenorhynchus asiaticus) 


CH 3 — (Chfe),, — C — O — (CHA — CH 3 

with n and m = even- or odd-numbered 


CH 3 — (CHA — C— O— (CHA — CH 3 

with a = 12-16 and b = 9-19 



CH 3 — CH2 — CH — (CH2) n — CH — C— O— (CH2) m — CH — CH 2 — CH 3 

I I I 

CH 3 CH 3 CH 3 

with n and m = even- or odd-numbered 

Figure 4. Chemical structures found in the preen waxes of Vultur gryphus, Ciconiiformes 
and Falconiformes. 

Preen wax types found in the uropygial gland of Ciconiiform birds 

Monoester waxes* Diester 

type I type II type III waxes Triglycerides 

Ciconia ciconia + — — + + 

Ciconia nigra*** + — — 4- + 

Xenorhynchus asiaticus*** + — — — — 

Egretta alba*** + + — — — 

Egretta sacra*** + + — — — 

Platalea leucorodia*** + + — — — 

Scopus umbretta + + — — — 

Theristicus caudatus ( + ) + — — — 

Threskiornis aethiopicus — + — — — 

Ardea cinerea + — — — + 

Ardea novaehollandiae*** + + + — — 

Nycticorax nycticorax + — + — — 

Botaurus poiciloptilus*** — + + — — 

Leptoptilos crumeniferus 


*type I: unbranched acids containing monoester waxes; type II; branched acids containing 
monoester waxes; type III: secondary alcohols containing monoester waxes 
**feather lipids 
***unpublished data 


In almost all Orders so far investigated, specific structures have been 
found so that species may be attributed to these taxa. There is, however, a 
remarkable exception to this in the case of the Ciconiiformes, where the 
composition of the waxes broadly varies. Not only the wax moieties but 

Bull. B.O.C. 112A 165 Integumental (uropygial) lipids 

also the total lipid composition itself differs among the various families, 
in that monoester waxes are found in Egretta, Threskiornis, Theristicus, 
Platalea and Scopus, whereas additional diester waxes and triglycerides 
are detected in Ciconia. In Ciconiiformes also species exist which possess 
secondary alcohols as one wax moiety (Botaurus, Nycticorax, Ardea). The 
findings summarized in Table 2 may indicate a polyphyletic origin for the 
order Ciconiiformes. 


From a chemotaxonomic viewpoint, the hitherto investigated species 
of the large order Passeriformes may be separated into at least 4 chemical 
groups according to their preen wax types: 

(1) waxes composed of unbranched alcohols and more or less highly 
methyl-branched acids substituted at every 4th carbon atom, with 
the first branch located at the 2- or 4-position. 
The following families or subfamilies may be attributed to this 
group: the Tyrannidae, Funariidae of the Suboscines, and also the 
Corvidae, Alaudidae, Bombycillidae, Oriolidae, Monarchidae, 
Timaliinae, Pachycephalinae, Hirundinidae of the Oscines. 

CH 3 — -(CHj.),, — CH— (CH 2 ) 3 — CH— (CH 2 ) 3 — - CH— C— O— <CH 2 ) m — CH 3 
CH 3 CH 3 CH 3 

(2) waxes composed of unbranched alcohols and 2-ethyl-substituted 
fatty acids. 

The Paridae and Troglodytidae may be combined in this group. 


CH 3 — (CH2> n — CH — C — O — (CHa),,, — CH 3 
C2H 5 

(3) waxes composed of unbranched alcohols and more or less highly 
branched fatty acids in which every 2nd carbon atom bears a 
methyl group, the first of which is located at carbon atom 2. 
The Ploceidae and Estrildidae are found in this group. 

CH 3 — (CH 2 ) n — CH — CH 2 — CH — CH 2 — CH — C — O — <CH 2 ) m — CH 3 
CH 3 CH 3 CH 3 

(4) waxes composed of 3-methylsubstituted alcohols and 3 -methyl- 
substituted fatty acids. 

To this group may be attributed the Fringillidae, Emberizidae, 
Passerinae, Motacillidae, Icteridae, Prunellidae, Carduelidae, 


CH 3 — (CHg),,— CH— CHz— C— O— CH2— CHa— CH— (CH2) m — CH 3 
CH 3 CH 3 

J.Jacob 166 Bull.B.O.C. 112A 

General considerations 

Generally speaking, there are Orders which are characterized by a 
very broad spectrum of different lipid constituents and others in which 
highly specific structures are found. Very complex mixtures occur in 
Sphenisciformes, Procellariiformes and Podicipediformes. A smaller 
complex of different acids and alcohols are found in Gruiformes, 
Falconiformes, Strigiformes, Psittaciformes, Anseriformes and Phoeni- 
copteriformes. In Galliformes, Coraciiformes, Cuculiformes, Piciformes 
and various Passeriformes the structural variation is even more restricted 
inasmuch as mostly only one homologous series of acids or alcohols 
participates in the spectrum of the preen wax. Extremely simple wax 
structures composed of only one acid and one alcohol have been detected 
in Cinclus cinclus (Bertelsen et al. 1975) and in many weaver-birds (e.g. 
in Ploceus cucullatus, P. subaureus, P. galbula — Poltz & Jacob 1973) 
indicating the presence of a highly specific enzyme system in these 

Since weaver-birds are considered to be more recent steps in avian 
evolution, it appears that preen wax patterns become more specific and 
less complex with progressing speciation — a trend which has also been 
observed for the cuticular lipids of beetles (Jacob & Hanssen 1985). 
Under the assumption that this is a general principle, an interesting 
conclusion may be drawn for the order Galliformes. The preen waxes of 
species from this order are characterized by the occurrence of alkane-2,3- 
diols for which 2 stereoisomeric forms are known (threo- and erythro-) 


CH 3 — (CHA — C — C — CH 3 erythro form 

I I 

H H 


CH 3 — (CH2V — C — C — CH 3 thre ° f ° rm 

I I 

(with n = even- or odd-numbered 

Mixtures of both forms have been found in Gallus and Coturnix, whereas 
Leipoa, Meleagris and Perdix possess only the erythro- forms. By contrast, 
Phasianus colchicus produces only one single diol, namely the erythro- 
octadecane-2,3-diol, i.e. a high stereo- and chain-length-specificity of 
the synthesizing enzyme(s) is expressed in this species. Following the 
hypothesis of a progressing chemical specialization, Gallus and Coturnix 
ought to be considered as ancient, Leipoa, Meleagris and Perdix as more 
recent forms and Phasianus as a preliminary endpoint of the evolution of 
the Galliformes. Within the closely related species Gallus and Phasianus 
and the couple Coturnix and Perdix, in both cases the second named are 
obviously the more modern forms. 


Summarizing the results of preen gland analysis obtained from about 
500 different species it seems that the wax composition is a helpful 

Bull. B.O.C. 112A 167 Integument al (uropygial) lipids 

parameter for avian systematics. The slogan "Show me your preen gland 
secretion and I shall tell you who you are" certainly exaggerates and 
overestimates the significance of this character. Preen wax analysis, how- 
ever, has contributed to the solution of several systematic questions and 
the data should be treated as one piece of a very complex puzzle. 


Beddard, F. E. 1898. The Structure and Classification of Birds. Longmans, Green, London. 

Bertelsen, O., Eliasson, B., Odham, G. & Stenhagen, E. 1975. The chemical composition of 

the free-flowing secretion of the preen gland of the Dipper (Cinclus cinclus). Chem. Scr. 

8: 5-7. 
Jacob, J. 1976. Diester waxes containing 2-hydroxy fatty acids from the uropygial gland 

secretion of the White Stork (Ciconia ciconia). Lipids 1 1 : 816-818. 

— 1978. Uropygial gland secretions and feather waxes. Pp. 165-211 in A. H. Brush (ed.), 

Chemical Zoology , Vol. X. 

— 1983. Zur systematischen Stellung von Vultur gryphus (Cathartiformes). J. Orn. 124: 

Jacob, J. & Hanssen, H.-P. 1985. Distribution and variability of cuticular hydrocarbons 

within the coleoptera. Biochem. Syst. Ecol. 14: 207-210. 
Jacob, J. & Hoerschelmann, H. 1984. Chemotaxonomische Untersuchungen an Eulen 

(Strigiformes). Funkt. Biol. Med. 3: 56-61. 
Jacob, J. & Poltz, J. 1974. Chemical composition of the uropygial gland secretions of owls. J. 

Lipid Res. 15: 243-248. 
Jacob, J. & Ziswiler, V. 1982. The uropygial gland. Pp. 199-324 in D. S. Farner, J. R. King 

& K. C. Parkes (eds.), Avian Biology, Vol. VI. Academic Press, New York. 
Konig, C. 1982. Zur systematischen Stellung der Neuweltgeier (Cathartidae). J. Orn. 123: 

Poltz, J . & Jacob, J . 1 973 . Biirzeldriisensekrete von Webervogeln (Ploceidae). Z. Naturforsch. 

28c: 449^152. 
Sibley, C. G. 1970. A comparative study of the egg-white protein of passerine birds. 

Peabody Museum of Natural History. Yale University , New Haven. Bull. 32. 
Sibley, C. G. & Ahlquist, J. E. 1972. A comparative study of the egg-white protein of non- 
passerine birds. Peabody Museum of Natural History. Yale University , New Haven. 

Bull. 39. 
— , — 1986. Der DNA-Stammbaum der Vogel. Spektr. Wissenschaft (5/86): 96-107. 
— , — 1990. Phylogeny and Classification of Birds. 976 pp. Yale University Press. New 

Haven & London. 

Address: Dr Jurgen Jacob, University of Hamburg, Zoological Institute and Zoological 
Museum, Martin-Luther-King-Platz 3, D-2000 Hamburg 13, Germany. 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 169 A. G. Knox & M. Walters 

Under the skin: the bird collections of the 
Natural History Museum 

by Alan G. Knox & Michael Walters 

Received 28 April 1 992 r | 

The bird collections of the Natural History Museum (NHM), formerly 
known as the British Museum (Natural History) or BMNH, have been 
housed at Tring, in Hertfordshire since the early 1970s. Increasing 
pressure on space at South Kensington in London caused the move out of 
town, to a site adjacent to the public galleries of the Zoological Museum at 
Tring. The latter had been bequeathed to the BMNH by Walter, Lord 
Rothschild, in 1937. The circumstances of the bequest, and the earlier 
sale of most of Rothschild's bird skins to the American Museum of 
Natural History, are described by Murphy (no date) and Rothschild 
(1983). The Tring public galleries are still maintained as a splendid 
example of a Victorian natural history museum, undoubtedly the finest in 
the country, devoted entirely to the spectacle of diversity. Some of the 
best taxidermy of the period is on display. 

This paper describes briefly the museum at Tring, outlines the scope 
and nature of the NHM bird collections and presents information about 
the specimens and their documentation. Attention is drawn to some of the 
possible sources of inaccuracy associated with museum data. Some of this 
information is relevant to any large collection. The curatorial comments 
may be of interest to staff with responsibilities for bird collections in other 

The NHM holds over one million bird skins, one million eggs, 13,000 
anatomical specimens and 8000 skeletons, making it one of the 2 largest 
bird collections in the world. It is particularly rich in historic material and 


The Tring site consists of 2 main buildings linked together. The older 
part contains the Rothschild public galleries, with offices, stores and part 
of the library behind and below. On the other side of the car-park is the 
purpose-built, 4-storey, air-conditioned block which houses most of the 
bird collections. Between these lies a single-storey building with security/ 
reception, offices, packing room, walk-in freezer, laboratory, staff room 
and a connecting corridor to join the main buildings together. Behind this 
block sits another large walk-in freezer and the separate dermestarium 
with a chemical store attached. The dermestarium consists of 2 rooms: an 
office/preparation area and the environmentally-controlled beetle colony 
where Dermestes beetles are used to strip carcasses. 

For further information on the Museum at Tring, see Clancey (1984). 


The NHM has the finest natural history library in the world. Most 
of the holdings are at the main Museum site at South Kensington, in 

A. G. Knox & M. Walters 170 Bull. B.O.C. 1 12A 

London, but the bird library is at Tring. It is probably the best bird 
library in the world concentrating on faunistics and works on taxonomic 
groups. Historically, the library comprised 2 main parts, the Rothschild 
Library (part of the bequest) and the library of the NHM bird section. 
The distinction is now less clear as the holdings have become integrated. 
At his death Rothschild's library was incomparably complete in the older 
literature and books on travel, exploration and big game hunting, and is 
housed in an exquisite 3-level balconied room. This area is not normally 
open to visitors. The remainder of the library at Tring is currently 
dispersed in several parts of the buildings. It is not a lending library, but is 
available to visitors by appointment and enquiries by post. Charges are 
made for photocopies. 

Storage units: the Tring cabinets 

Most of the bird skins, as well as the eggs, nests and skeletons are stored 
in specially constructed cabinets. 

These cabinets consist of two 2-door units one on top of the other. Each unit has a 
removable central divider and may thus take either full- or half-width plastic drawers 
sliding on plastic runners. The carcasses of the cabinets are constructed from chip-board, 
which works well with half-width drawers, but has bowed slightly on some cases allowing 
some full-width drawers to drop. This is easily corrected with small wedges between the 

The doors are metal skinned, with refrigerator-type magnetic seals. The plastic skin on 
the door seals has become tacky on many units, and the adhesive bonding the metal strip to 
the carcasses has failed in places. Each door has a label holder on the outside and a recessed 
pocket for insecticide within. The door pockets in the bird skin cabinets contain insecticide, 
which is changed twice yearly. Until recently ceramic tiles impregnated with DDVP 
(Dichlorvos) were used, but these have been replaced with commercial Secto units in plastic 
cases. Severe corrosion is usual around the pockets, and ink from fibre-tipped pens used to 
label the drawers smudges and becomes illegible near the pockets. Pesticide levels within the 
cases are said to conform with recommended levels, but there is a strong odour on opening 
the doors and some users have experienced persistent headaches. Visitors to the collection 
are recommended to open the cases and allow them to ventilate before working with the 
specimens. The continued use of DDVP is being reviewed. 

Within the half-width drawers many of the specimens are held in heavy, plastic-laminated 
cardboard trays in 5 modular sizes from 2 to each drawer down to 32. 

The skins of many species have been divided into subspecies, and within each subspecies 
into separate sexes, age classes or by geographic origin as appropriate. The labels of the birds 
in each group are marked with numbered and coloured gummed paper spots and, for small 
birds, the groups are put in separate trays. This system has been found to aid research and 
curation, and helps users to return skins to the correct trays. Trays containing groups of 
interest may easily be carried to side benches for study. 

The use of plastic drawers and laminated trays help to reduce abrasion on the skins 
and minimize the soiling of feathers which may occur in drawers constructed from less 
sympathetic materials. 


Spirit and skeleton collections 

The ground floor of the main (new) building contains the spirit and 
skeleton specimens. The spirit collection is held in 70% industrial 
methylated spirit in the usual variety of bottles and jars on metal racking. 
Glass-topped bottles and jars with ground-glass stoppers are preferred, 
the most recent ones having been purchased from eastern Europe. 
Plastic-topped containers are being replaced whenever possible. Most of 
the larger specimens are contained in plastic buckets with lids, but the 

Bull. B.O.C.W2A 171 BMNH bird collections 










i — ■ — i — ' — i — ' — i — • — i — ' — i — • — i ■ i ■ i 

1840 1860 1880 1900 1920 1940 1960 1980 2000 

Figure 1. Growth of the Natural History Museum collections. Horizontal axis: year. 
Vertical axis: number of completed Aves registers (including sets of Special Collections 
Registers). The open symbol indicates a volume half-completed in 1992. (The use of the 
Registers in this way gives only an approximation of the growth of the collections.) 

buckets occasionally split. The collection is arranged in systematic order 
following Peters (1931-87), the main exception being a metal cabinet 
housing extinct birds and historic or otherwise important specimens, 
including 2 birds collected on Cook's last voyage, one of which is still in its 
original bottle. 

All but the largest skeletons are held in glass-topped boxes with labels 
clearly visible so that the contents may be checked without the need to 
open them. Several cabinets are reserved for important material, separate 
from the main systematic series. 

The holdings of the anatomical and skeleton collections have recently 
been summarised by Blandamer & Burton (1979), Wood & Jenkinson 
(1984), Wood &Schnell (1986) and Wood etal. (1982a, 1982b). There are 
no skin-skeletons or long series of skeletons of individual species, or 
special tissue collections for biochemical research. 

The skin collection 

The large skin collection contains representatives of almost every 
species and subspecies listed by Peters (1931-87). In terms of numbers of 
individuals, geographic coverage is best for the Palaearctic, Africa, India 
and North America, and poorest for South America. 

The collection dates mainly from the late 1 9th and early 20th centuries, 
and relatively little material has been acquired in the last 40 years (Fig. 1). 
Only 7 new skins were registered in 1986, and fewer than 50 per year is 
now usual. 

A. G. Knox & M. Walters 172 Bull. B.O.C. 112A 

Most of the bird skins are on the first, second and third floors of the 
main building. The birds are arranged in systematic order with the non- 
passerines starting on the top floor and working down to the first floor 
with the 'near-passerines' and all the passerines. The first floor also holds 
segregated series of the types (c. 8000), the extinct and endangered birds 
and a few historic or delicate collections (e.g. the Montagu collection). 

Large bird skins are held in part of the adjacent Rothschild building 
in cabinets with good frameworks and drawers, but with poor fronts 
constructed from modified plastic roller-blinds which often jam. They 
are also neither insect- nor dust-proof which is regrettable as the 
Rothschild building is environmentally less satisfactory. Rothschild's 
large collection of mounted cassowaries Casuarius haunt the basement 
of this building in even poorer conditions, but 'poor' is relative in this 
context. Most museums would envy even the worst store-room at Tring. 

A separate building (the Annex) in the same street is used as a general 
store and houses the Museum's collection of mounted birds without data, 
many on open shelving with roller-blind fronts. 

Condition of the skin collection 

Being a very old collection, with relatively little recent material, many 
of the skins are not in the best of condition. Amongst the large birds in 
particular, damage from grease is common. The smaller birds suffer more 
often from detached legs, wings and heads, and this is worst in frequently- 
used groups such as the Phylloscopus warblers. Detached labels can occur 
anywhere in the collection, often the result of grease damage and/or 
embrittlement of the paper or poor handling or both. These problems will 
get worse rather than better as the collection grows still older and is used 
more, highlighting the conflict between use and conservation. Indeed, the 
oldest and most historically important specimens are amongst those at 
greatest risk. The need for adequate conservation resources is a problem in 
most bird skin collections throughout the world and, until it is addressed 
properly, irreplaceable specimens will continue to be threatened. 


There is no card- or other index to the whole collection, indeed only the 
extinct and endangered birds have been entered onto computer (Knox & 
Walters, MS). Apart from the information on the labels, field-notes that 
may have been lodged in the library and anything that may have been 
published about individual specimens, the only documentation to the 
collection is the Registers or the old Catalogues (see below). The monu- 
mental, 27 volume, Catalogue of Birds in the British Museum, published 
between 1874 and 1898 (Sharpe and others 1874—98), contains some 
details of the specimens in the collections at the time each group was 
revised. This work frequently reveals information on extant specimens 
that is not on the labels, and indicates where other specimens have since 
disappeared to or have been reidentified. 


The quality of data associated with specimens in many museums, par- 
ticularly the older specimens, is extremely poor and often contradictory. 

Bull. B.O.C. 1 1 2A 173 BMNH bird collections 

This problem has been discussed previously by e.g. Van Tyne (1952), 
Clench (1976), Conover & Hunt (1989) and Parkes (1989a,b). Recommen- 
dations for critical data have recently been made by Foster & Cannell 
(1990). In the following section, although we discuss the quality of the 
data with particular reference to the collections of the NHM, many points 
apply equally to any large collection. 

Museum registration numbers 

Many specimens, skins in particular — perhaps as many as 100,000 — 
have never been registered. In other cases, specimens were dealt with in 
blocks — for instance, a large part of the great Shelley collection occupies 
only 7 lines in the register. 

Attempts to check numbers on labels against the original register entries 
reveals many irregularities. Some numbers were written incorrectly on the 
labels (or even in the register): given time, most, but not all, of these may be 
traced. Duplicate numbers are sometimes encountered. Many arise from 
the Special Collections registers (see below), but for others it is clear that 
2 or more specimens (usually, but not always, with the same data) were 
registered with the same number without this information being noted in 
the register. Details of the Registers and Catalogues of the collection are 
given below. 

Locality data on labels 

Tracing place-names is often a difficult task, particularly with older 
museum specimens. The handwriting on labels is frequently illegible or 
nearly so, and may be in a foreign language or a collector's shorthand. 
Local names which do not appear on maps or in gazetteers are regularly 
encountered. Much collecting took place before detailed maps of the 
relevant countries had been prepared, and at a time before place-names 
had ever been written down. It was not unknown for a collector to use 
several different spellings for the same place-name, or different names for 
the same place. Some common place-names can be found repeatedly 
within a single country and in some countries place-names change 
with the political climate. Chinese place-names have their own special 
problems, as do many from the Near East. 

Two other significant practices serve to introduce uncertainty concern- 
ing many of the apparent localities of older specimens. The first relates to 
localities not noted at the time of collection, the second, to the widespread 
removal of original labels. 

The importance of precise locality (or any other) information was not 
recognised by many early collectors; large numbers of specimens bear no 
data at all or, at best, a country or continent alone. Other collectors made 
up labels long after the specimens were obtained, with the attendant 
possibility of errors of memory or transcription. A few unscrupulous 
collectors or dealers fabricated data to enhance the monetary or scientific 
value of their specimens (e.g. see Nicholson & Ferguson-Lees 1962). 
The huge Meinertzhagen collection at the NHM has many skins bearing 
incorrect data, including a number taken from the then BMNH and 
subsequently relabelled (for the evidence see Clancey 1984, Cocker 1990: 
274—5; also A.G.K. pers. obs.). 

A. G. Knox fe? M. Walters 174 Bull. B.O.C. 112A 

Specimens were frequently obtained in batches from collectors (often 
native) and shipped through dealers and transit ports and, at any stage of 
this process, erroneous data could become associated with the specimens, 
inadvertently or otherwise. Some dealers (and even museums) attached 
their own labels, often carrying generalised distribution data relating to 
the range of the species rather than the locality of the individual. The data 
were not even safe when the specimens reached the British Museum. For 
a while, localities and dates were routinely transferred to Museum labels, 
and all others removed (Sharpe 1 906). Many errors arose in this way. The 
practice was not that of the British Museum alone, but was widespread 
among curators until the late 19th century. Where additional labels had 
been attached to specimens and the earlier ones retained, errors of 
transcription are frequently noted. Examples may be found in Knox & 
Walters (MS). 

Particular care is required when dealing with specimens which are 
mounts or ex-mounts. For a long time during the 18th and early 19th 
centuries all important specimens were set up for display in the public 
galleries of the Museum. Such specimens usually had their labels removed 
and, with some, the data written on the base of the mount or printed on the 
accompanying gallery label. Few of the latter still exist and many of the 
old gallery specimens have since been unmounted and transferred to the 
general skin collection. Most specimens which were formerly mounted 
(or are still mounts) lack data; with others there are doubts concerning 
the veracity of data after repeated transcription. In a few cases it is clear 
that when gallery specimens became damaged, or better ones became 
available, birds were substituted without necessarily changing the data. 
Some were placed on mounts formerly occupied by conspecifics or quite 
different species. Since the late 1980s, the Museum has not unmounted 
birds for them to be placed in the general skin collection, as the former 
practice often led to the loss of information concerning the history of the 

Date of collection, or date of death of specimens from captivity 

Many of the comments made above regarding the reliability of locality 
data apply equally to the date, where the information may have been 
transcribed several times or added long after collection. At its worst, 
during the preparation of the Catalogue of Extinct and Endangered Birds 
(Knox & Walters, MS), three different dates (without comment) were 
found on separate labels attached to a single specimen. 

The labels on many specimens, particularly from the Salvin-Godman 
and Sclater collections, bear dates usually consisting of the year, or the 
month and year only, written close to the thread holes at the left-hand 
end. In some cases it appears that these are the dates of collection and in 
others, that they are the dates when the specimens were received. Where 
the label bears only one date, it is not possible to tell which it is. Where 2 
dates appear, they are sometimes the same but, more usually, the left-hand 
one is later. 

The labels to some older bird skins also bear the dates when the speci- 
mens were sent to the 'stuffers', usually to be unmounted, cleaned or 
repaired. It is only too easy to mistake this for the date of collection, 

Bull.B.O.CAUA 175 BMNH bird collections 

particularly if the latter was not recorded. The stuffer's name (not always 
given) or a date several decades after the year of registration are the main 
warnings, but some stuffers' dates are disturbingly plausible as dates of 
collection. The NHM still holds several volumes of notebooks recording 
the movements of specimens to and from various stuffers, including 
Burton, Cullingford, Dodson, Gerrard, Gunn, Pickhardt, Rye and West, 
for the period 1871-1895. 

Information on the original collector (if known), or the route by 
which the specimen reached the Museum 

The names of the original collectors, dealers, private qollectors and 
other intermediaries through whose hands and/or ownership the speci- 
mens passed before they came to the Museum have caused almost as many 
problems as the place-names. Alternative spellings, difficult handwriting, 
initials without full surnames and other missing or incomplete data 
pervade the collections and the registers. 

For information on many collectors and donors, see Sharpe (1906), 
Warren & Harrison (1966-73) and Mearns & Mearns (1988). 

Age and sex data 

Although many or most specimens were probably examined internally 
at the time of collection, this is rarely noted on the label. A proportion of 
specimens will have been mis-sexed, for 2 main reasons. Firstly, for some, 
sex will have been determined on the basis of (incorrectly) presumed 
plumage or mensural differences, either on collection, or at any time 
subsequently. Secondly, mistakes may have been made in the internal 
sexing of specimens that were damaged or partly decayed, or with small 
sexual organs (particularly during the refractory period). Careful sexing 
(with notes and sketches of the gonads, and the name of the preparator) 
is particularly important with skeletal material, in which there is the 
additional danger of misidentification of species. Fig. 2 illustrates 
mis-sexing in some skeletal material. 

For further discussion on the reliability of sex information on museum 
labels, see Clench (1976) and Parkes (1989a,b). 


Occasional reference will be found on labels or in the literature to 
'duplicates'. For a long time (since the late 1700s) it was the practice to 
select only the best specimens for the NHM's collections, and consign the 
others to the 'duplicates', in the basement. Very large numbers of birds 
were so designated. They were kept separately from the main series, and 
the labels were usually annotated 'duplicate', 'dupl.' or 'dup.'. These 
birds were often used for exchange or presentation. Storage space was 
always at a premium when the bird collections were held in London, 
either at Bloomsbury, or later at South Kensington. From the 1940s until 
the late 1960s, many drawers were so full that specimens without good 
data were removed and sent to Tring Zoological Museum, where the 
'duplicates' were then housed. Similarly, poor specimens, or ones with 
incomplete data from newly received collections were dispatched regu- 
larly by van to Tring. Although the assignment of new duplicates has 

A. G. Knox & M. Walters 



<o 45 _ 

Bull.B.O.C. 112A 

99 999 
9 9 99 9 

9 9 •" 
9 rf 9 •" 

cr ^ cf cr 


t — i — r 


l — i — i — i — r 


t — i — r 


keel length (mm) 

Figure 2. Skeletal measurements of British Sparrowhawks Accipiter nisus in the Natural 
History Museum, registered 1951-1988. Symbols denote sex as shown on the box labels. 
Filled symbols indicate specimens presumed to have been sexed incorrectly. Most species of 
birds show less sexual dimorphism in size than the Sparrowhawk and mis-sexing would be 
more difficult to test in their case. 

ceased, it has not yet been possible to reincorporate all the previously 
separated material, and drawers or trays marked 'duplicates' may still be 
found in the collection. 

Missing specimens 

Specimens known or thought to have been in the collections are some- 
times unable to be located. Indeed, a significant number of specimens 
could not be found during a recent NHM cataloguing project (Knox & 
Walters, MS). Specimens which are listed in the registers, in the 
Catalogue of Birds or elsewhere can appear to go missing for a variety of 
reasons. Some will have been re-identified and moved to a different part 
of the collection; some will have been exchanged or given away; a few will 
even have been so badly damaged by insects or other causes that they have 
been subsequently destroyed. In all these cases, it would have been usual 
to annotate the register accordingly, but this sometimes was not done. 
Furthermore, specimens are not infrequently put back in the wrong place 
in the collection by visitors (and occasionally by staff): with a collection as 
large as that of the NHM, it becomes difficult to relocate specimens 
misplaced in this way. Some genuinely will have been lost, and a few will 
possibly have been stolen (see e.g. Clancey 1 984). A quantity of eggs from 
the Jourdain collection were never actually received, although the card- 
index might suggest otherwise. Likewise, some other specimens that the 
Museum is said to possess, never arrived, and a small number of entries 

Bull. B.O.C. 1 1 2A 177 BMNH bird collections 

may be clerical errors. Many older labels were made of flimsy paper or 
card that has become brittle. When the specimens became separated from 
their labels (as many of them did), they became unrecognizable and, 
effectively, lost. 

The Old Collection 

As far as we can ascertain, the term 'Old Collection' has been used in a 
variety of contexts. It seems to have been applied to the collection which 
was housed in the public rooms of Montagu House in the early 1800s, at 
least part of which was then moved to the galleries of the new British 
Museum (completed on the same site in 1845). Some specimens remained 
on show until at least the 1870s, but others were removed from time to 
time and placed in the study collections. 'Old Coll.' appears without 
definition in the Catalogue of Birds, apparently referring to various old, or 
not so old, usually unregistered, specimens. The term has also been used, 
seemingly without much discrimination, at various other stages. 

Type specimens 

Many labels bear the inscription 'type'. Most of these do not refer to 
name-bearing types, but to specimens that are 'typical' in some way. 
Holotypes and syntypes identified or selected by Warren & Harrison 
(1966-73) and others are segregated into separate cabinets and carry red 
labels for easy identification. 

Additional comments 

The collection mainly being old, the labels rarely carry information 
about bare-part coloration, stomach contents and so forth. 


Like the skeletons, the egg collection is stored in clearly labelled glass- 
topped boxes. Within each box the eggs rest in individual depressions in 
cotton wool, restrained from movement which could damage them 
during curation or while being studied. The boxes also provide additional 
protection against atmospheric particulates. For security, the cabinets are 
locked and unlabelled. 

Approximate size of the collection 

The egg collection is believed to be the largest in the world. The 
eggs have never been counted and, because eggs are usually kept and 
catalogued in sets or clutches of varying size, the number of items 
catalogued is not an indication of the total size of the collection. (A set is 
regarded as one or more eggs of the same species collected or received 
together, not necessarily a clutch.) About half the cabinets in the system- 
atic series have been revised and, by random counts of specimens in the 
remainder, an estimate of c. 1,000,000 eggs has been made. To arrive at 
an average number of clutches it might be necessary to divide this total by 

A. G. Knox & M. Walters 178 Bull. B.O.C. 1 12A 

The age of the specimens 

Only a few of the Museum's eggs are more than 150 years old. The 
earliest so far found is of a Northern Gannet Morus bassanus from the Bass 
Rock, in Scotland, collected in 1807. It is probable that some undated 
eggs are older than this. A number are labelled 'Old Collection', and 
among them are probably the ones referred to by Lankester and by Oates 
on pp. v and vii of Oates (1901). These were from a very early collection 
displayed in the public galleries. Many of the eggs listed in the main text 
of Oates (1901-12) as being from the Old Collection were more recent, 
having been acquired from nineteenth century dealers such as Fraser, 
Warwick and Parzudaki, though they share with the old eggs the lack of 
data and dates. There are also a number of eggs listed as 'Montagu collec- 
tion' or 'ex Montagu Museum'. These were probably received at the same 
time as the Montagu collection of bird skins (1816) and some may be of 
eighteenth century vintage. 

Most of the Museum collection (about 90-95%) dates from the latter 
half of the nineteenth century and early part of the twentieth. Apart 
from the Pitman and Benson east African collections, and more recent 
confiscations of eggs taken illegally in this country, there is little material 
from later than about 1940. 

Systematic coverage 

The eggs are stored and curated in systematic order, following Peters 
(1931-87). There are specimens from all orders and nearly all families, 
apart from a few which are monotypic. The nests and eggs of about one 
third to one quarter of the world's species may still be undiscovered or 
undescribed; in addition, a number of species from remote areas are not 
represented. Nevertheless, this is probably the most comprehensive 
collection in the world. 

There are particularly good series of Ratites (including the Tinamidae), 
Cuculidae, and especially Uria aalge. 

Special collections 

In addition to the systematic series, some collections are kept 

Eggs of varieties of domestic poultry. 

Six eggs of Pinguinus impennis. 

Stuart Baker's collection of Cuculus canorus. It has not been practicable 

to incorporate in the main collection the eggs in all the boxes of this 

Chance Collection, still in its own cabinets. 

Geographic coverage 

Most collecting occurred when the colonial powers of the northern 
hemisphere were in their heyday. This is reflected in museum collections 
of that period, and those of the NHM are particularly rich in African and 
Indian material. Local and national museums may have more complete 
local collections but few, if any, have the general coverage of the NHM. 
However, where we have indicated that the Museum's coverage is 

Bull. B.O.C. 1 1 2A 1 79 BMNH bird collections 

weakest, it should not always be assumed that better collections exist 
elsewhere. Degree of coverage is given below by regions. 

Western Palaearctic. Very good. 

Eastern Palaearctic. Not good. The best represented area is Japan from 
whence the collector Owston sent a considerable amount of material to 
Rothschild. There are also collections by Katsumata from Hainan and 
Tancre from central Asia (particularly the Altai and round Issyk Kul 
Lake). All of these were received with the Rothschild bequest. The 
Museum also holds the collections of La Touche, Rickett, Styan and 
Swinhoe; these are mainly from south China. 

Middle East. Patchy and poor. Some good collections from southern 
Iraq and the northern end of the Persian Gulf, but otherwise 
comparatively little. 

Africa north of the Sahara. Poor. There are collections made by 
expeditions to Morocco under Salvin, Tristram and others in the 1 850s 
and by Rothschild and Hartert in the early years of the 20th century. 
Some collectors such as Aharoni collected in the Sahara (and also in the 
deserts of the Middle East) but these collections are small. 

Afrotropical Africa. Good, but patchy. Parts of east Africa were well 
worked by collectors such as Benson and Pitman, but there is very little 
from west Africa. Angola and Gabon are represented solely by material 
from Ansorge, a botanist who collected anything he found, including 
quite a number of birds with their nests and eggs. He apparently knew 
little about birds and the identifications were made later; there is thus a 
small element of doubt with some. From South Africa there are the 
Layard collections (usually with no data) of the nineteenth century, and 
one or two small collections such as that of Bernard Jupp. 

Burma and the Indian sub-continent. Excellent. Mostly the work of 
British Army officers and civil servants, these are probably the best in 
the world for this area; an incomparably rich collection. 

Southeast Asia. Almost nothing except the E.G. Herbert and Sir Walter 
Williamson collections made near Bangkok, Thailand. Both contain 
good series of local species. 

Indonesia. Almost nothing, this area formerly being under Dutch 
influence. There are collections by Whitehead and Sir Hugh Low, both 
from British Borneo, and the Steere Expedition specimens from the 
Philippines. This area is the most poorly represented in the whole 
Museum collection. 

Melanesia and the Papuan regions. Not good. Rothschild's collectors 
moved through this area and collected extensively, but eggs were 
nowhere taken in quantity. 

A. G. Knox & M. Walters 180 Bull. B.O.C. 112A 

Australia and New Zealand. Not good. A number of eggs are of 
historic interest, particularly those from John Gould and Sir Walter 
Buller. A list of Australian eggs in the collection was drawn up in the 
1 960s prior to the Harold Hall Expeditions. This is no longer complete, 
due to more recent acquisitions. 

Pacific Ocean. Poor overall, but there are long series of some species from 
particular islands, such as Norfolk, Lord Howe and the Galapagos. 
Many islands are not represented at all, and most are represented only 

North America. Rather poor, mostly dating from the 19th century. 

Central America. Very poor. Very little collecting seems to have been 
done here by the British, apart from Godman and Salvin during the last 

South America. Very poor on the whole but, for a high proportion, the 
eggs of South American species are still unknown. There are good 
collections from Trinidad and the Falklands, and long series from 
places like Los Yngleses (a British-owned estate near Buenos Aires 
belonging to the Gibson family) but the general coverage is not good. 
Other important collections include those by Berkeley James from 
Chile, and Venturi from Patagonia. 

In summary, the collection possesses probably the best assemblage of 
eggs of the Indo-Burmese area, and possibly the best general collection 
for Africa. It is weak in specimens from North and South America and 
Southeast Asia. 

Some collections of particular interest 

Stuart Baker collection. The largest collection of Indian eggs and, 
although a few specimens are suspect, some species are not known to be 
represented in any other collection. 

T.R. Bell collection. A fairly large Indian collection, which arrived in its 
original boxes with each egg individually wrapped in cotton wool. Bell 
worked for the Forestry Commission in India in the late 19th and early 
20th centuries. His field diaries are in the Entomology Library of the 
NHM at South Kensington. 

Edgar Chance collection. Completely card-indexed, this collection 
arrived in its own cabinets. As it was well housed and beautifully laid 
out, it has never been incorporated with the main collection. Chance 
wrote several books on the Cuckoo. 

Philip Crowley collection. At the turn of the century, this was the 
largest egg collection in private hands. A proportion of it was acquired 
by the Museum about 1901-2, the rest was dispersed and may now be 
lost. So, too, are his original catalogues. Some species are still, after 
nearly a century, represented only by eggs from this generous bequest. 

Bull. B.O.C. 1 1 2A 181 BMNH bird collections 

J. Davidson collection. This large Indian collection was received about 
1925 and, although much of it has been incorporated, a great deal 
remains to be done. Davidson had sorted and catalogued part of it after 
his return from India. A considerable amount seems never to have been 
unpacked, and reached the Museum in the original boxes in which it 
travelled back from India. The eggs had not been sorted into clutches, 
or even species. They are identifiable only by species numbers written 
on them, the numbers referring to one of 2 lists of Indian birds. Like 
Bell, Davidson apparently worked for the Forestry Commission in 

J.H. Gurney collection. Incorporated in 1955, this was formerly at 
Norwich Castle Museum. It consists only of birds of prey and owls, but 
includes some species not otherwise represented in the collection. 

A.O. Hume collection. The first large collection of Indian eggs, 
received in the 19th century. Hume was one of the most significant 
early contributors to Indian ornithology, and published his own 
journal Stray Feathers. 

F.C.R. Jourdain collection. This huge collection must be one of the 
most important for the Palaearctic. 

H. Munt collection. Henry Munt specialised in white eggs, and in eggs 
from birds in captivity (he seems to have been in close communication 
with many breeders). His collection contains many rarities. The 
collection was registered in 1941. 

J.D. Salmon collection. Formed in the early nineteenth century, and 
donated to the Linnean Society in the 1860s, before subsequently 
coming to the Museum. 

H. Seebohm collection. The earliest large collection of Palaearctic 

Rodern collection. Count von Rodern's collection was acquired by 
Rothschild towards the end of last century. It was apparently 
accompanied by 2 catalogues: one printed, and a manuscript written by 
Max Kuschel, the well-known German oologist. These were last seen 
at Tring in the 1950s, when Glegg mentioned them in a note in the Ibis 
(1951: 305-6). They subsequently disappeared. The collection is poorly 
documented but contains some interesting specimens, including series 
showing wide ranges of colouring within selected species. 

Eggs of particular interest 

An egg of the extinct Syrian Ostrich Struthio camelus syriacus, which 
passed in turn from Charles Doughty to Col. T.E.Lawrence 
(Lawrence of Arabia) and Col. Richard Meinertzhagen. 

The only known egg of the extinct Kangaroo Island Emu Dromaius 

A. G. Knox & M. Walters 182 Bull. B.O.C. 1 12A 

A clutch of eggs of the Emperor Penguin Aptenodytesforsteri collected by 
Cherry-Garrard (Cherry-Garrard 1922). 

Two putative eggs of the extinct Labrador Duck Camp tor hynchus 
Iabradorius. There are no eggs of this species whose authenticity is 
above question (contra Greenway 1 967: 1 74; see also correspondence at 

Type specimens of Anthus venturi and several putative species of 

The only eggs of the extinct rails Cabalus modestus and Pareudiastes 

An English egg of the Great Bustard Otis tarda from the Montagu 
Collection; the Great Bustard last bred in England about 1840. 

H.L. Popham's clutch of the Curlew Sandpiper Calidris ferruginea; this 
was the first clutch ever found of this species, and is still the Museum's 
only clutch. 

Six eggs of the Great Auk Pinguinus impennis. The Museum also holds a 
number of plaster casts and models of Great Auk eggs, often carefully 
painted in the colour and pattern of particular specimens in other 
collections. There is also a remarkable fake, an egg of a swan which was 
painted to resemble that of a Great Auk. It was part of the J . D . Salmon 
collection (see above) and had been substituted for a real Great Auk egg 
in that collection, sometime between Salmon's death and the acquisition 
of his collection by the NHM. 

Eggs (and nests) of the extinct Laysan Millerbird Acrocephalus 
familiar is. 

Five eggs collected by Audubon. All seem to have been acquired by H.B. 
Tristram, whose collection passed to Crowley. The Museum received 
many of Tristram's eggs with the latter's bequest. The Museum also 
has Tristram's complete catalogues. It is probable that other Audubon 
eggs await discovery. 

There are a number of eggs of other extinct species, together with 
specimens collected by well-known ornithologists such as Ayres, S.F. 
Baird, D. G. Elliot, Heermann and Krider. Many of these are without 
data and had been set aside as 'duplicates', although they have now been 

Unincorporated collections 

Neglect of the egg collection during the early and middle 1900s led to a 
considerable backlog of incorporation. There are a number of valuable 
acquisitions, estimated at 30—40,000 eggs, which are still partially or 
entirely unincorporated. Since these are not in a state in which they could 
be used by visitors, this represents a great loss to the collection. 

Col. E.A. Butler collection. A very good collection, mainly from India, 
Ceylon and northeast Africa. Registered but still only partly incorpor- 
ated. Butler was an army officer who collected eggs as a hobby and 
published a number of papers. His collection was received by the 
Museum as part of the Rothschild bequest. 

Bull.B.O.CAUA 183 BMNH bird collections 

Chance collection. See 'Some collections of particular interest'. 

Davidson collection. See 'Some collections of particular interest'. 

Jourdain collection. Several cupboards contain the residue of this vast 
collection, which formed part of the Hewitt bequest (the rest of which is 
now at the Delaware Museum). The eggs were very mixed-up when 
they arrived at the Museum, and considerable numbers still cannot be 
matched with the relevant data. 

Letchworth Museum collection. A mixed assemblage, but includ- 
ing some quite rare eggs of North American waders. Only partly 

Capt. Pitman collection. The late Captain C.R.S. Pitman, probably the 
most important east African collector, presented his eggs in small 
numbers over a period of time. Much has been incorporated, but some 
still awaits study. 

H.L. Popham collection. An important Siberian collection; still only 
partly incorporated. 

Rodern collection. See 'Some collections of particular interest'. A por- 
tion of this collection awaits incorporation. 

South Kensington. A batch of eggs received about 1981 seems to be 
part of an old collection formerly in the public gallery. It includes a 
number of very old specimens registered prior to 1880 and not listed in 
Seebohm's ms catalogue (see below). 

Tait collection. Put together by a well-known English ornithological 
family resident for some years in Portugal, and presented to the 
Museum some time after the death of the last surviving member living 
there. The eggs are very dirty and, until recently, were unsorted. The 
data slips (in Portuguese) have also become separated from the rel- 
evant clutches. This collection contained the only known eggs of the 
Guillemot Uria aalge from Portugal, and these have been incorporated. 

William Borrer Tracy collection. British eggs of historic interest 
presented by Rear Admiral H.G.H. Tracy in 1979. 

F.E.W. Venning collection. Venning worked mainly in Iraq, Pakistan 
and Burma, where he was one of the most important collectors. He was 
exceptionally meticulous. The collection was accompanied by detailed 
notebooks containing a wealth of data on each clutch, mainly relating to 
nest site and nest construction, incubation and so forth. It has only been 
partly incorporated, and most of Venning's valuable data seems never 
to have been published. 

A. G. Knox & M. Walters 184 Bull. B.O.C. 112A 

S. Venturi collection. A South American collection of great import- 
ance, written up by Hartert & Venturi (1909). Part of the Rothschild 
material. Most has been incorporated. 

Waller collection. A large collection of general interest, received in the 

Whitehead collection. John Whitehead was a famous explorer and 
collector who visited and wrote about Mt Kinabalu, Borneo. He subse- 
quently died while on an expedition to Hainan. His collection of 
European eggs was acquired by Rothschild and bequeathed to the 
NHM. Mostly incorporated, but a small part remains. 

P.F. Wickham collection. A collection of Burmese eggs presented by 
Exeter Museum in the 1980s in exchange for some mounted skins. 

The history and status of curation 

The egg collection was last completely revised and catalogued in the 
1 890s, by Henry Seebohm. It was set out and labelled at this time by Miss 
Emily Mary Sharpe (Dr Bowdler Sharpe's daughter), since when many 
boxes remain unaltered. Seebohm prepared a manuscript catalogue (still 
held in the Egg Section) of all the specimens in the study collection. This 
did not include eggs in the public galleries and, in recent years, some of 
these have been retrieved and incorporated. The galleries were raided 
from time to time by members of the public, and many eggs are now 

Between 1901 and 1912 the 5 volumes of Oates's Catalogue of the collec- 
tion of birds' eggs in the British Museum ( Natural History ) were published 
by the Museum (Oates 1901—12). They were based on Seebohm's manu- 
script, but included many additional specimens. The introduction to 
volume 1 contains further details of the history of the collection. 

Curation of the collection over the subsequent 60 years seems to have 
been fitful, though a card-indexing system was started quite early on. Its 
coverage was no more than perfunctory and work seems to have ceased on 
it after a short time. Only a small number of the original cards have been 
found, mostly relating to birds of prey. They are beautifully written and 
demonstrate detailed and meticulous research. The writing appears to be 
that of the Rev. F.C.R. Jourdain. 

Although Walter Rothschild's bird skins from Tring were sold to the 
American Museum of Natural History in 1932, he retained his sizeable 
egg collection. The latter passed to the Natural History Museum on his 
death in 1937, the largest acquisition ever received. During the 1940s, 
W.E. Glegg sorted and registered parts of it, a task continued by Mrs F.E. 
Warr in the 1950s. Rothschild's material was an assemblage of separate 
collections brought together by him, mainly by purchase. 

Mrs Warr was also responsible for initiating the accessions index for 
the Museum's egg collection. For a time, Rachel Warren worked on parts 
of the Davidson material, but most of her cards have now been replaced. 
Some donors of small collections wrote their data directly on to Museum 
cards and these are preserved in the index. Envelopes, the same size as the 

Bull. B. O.C.I 12 A 185 BMNH bird collections 

cards and similarly printed, are used to hold original labels, letters or 
similar material relating to the relevant eggs. 

In 1960 an attempt was started by C.J.O. Harrison and S. Parker to 
recatalogue and completely card-index the collection. From this date 
onwards all eggs received and incorporated — a considerable number — 
were card-indexed, and given a new style of label. Prior to the NHM's 
Harold Hall Expeditions (Hall 1974), all the Australian material was 
revised and card-indexed, mainly by Mr Parker, although more has since 
been added. 

From 1970 onwards, MW has worked on incorporation and the sys- 
tematic revision of the entire collection. Most of the cards from this 
period have been typed, whereas the bulk (though not all) of the previous 
ones are handwritten. The non-passerines and sub-oscine passerines 
have now been revised and card-indexed. Data extracted from the 
Seebohm and Oates catalogues have been added to the cards, and entries 
have been made (in red ink) for eggs no longer in the collection. 

During the 1970s there was a series of systematic thefts by a visitor, 
Mervyn Shorthouse, who had been using the collection regularly. 
Between 1975 and 1979, an estimated 30,000 eggs were stolen before he 
was apprehended (and subsequently convicted). About 10,000 eggs were 
recovered, but the usefulness of many is limited, and the integrity of large 
parts of the egg collection has been jeopardised. As well as removing eggs, 
Shorthouse often substituted specimens from elsewhere in the collection 
to fill gaps and, in some instances, deleted and replaced registration 
numbers to conceal his activities. Many of the recovered eggs had data, 
set-marks and registration numbers removed from them, making it diffi- 
cult to match the eggs with their data. The collection has since been 
carefully revised through to the Alaudidae. Until the revision is complete 
(which will take some considerable time), the remaining passerine eggs 
can only be used with great care. 

The nest collection 

The nest collection contains only about 2000 specimens, of which 
probably fewer than 200 are non-passerines. The coverage is poor in 
every way, although no detailed investigation has been carried out. It is 
less of a collection than an accumulation of miscellaneous material which 
happened to be deposited with the Museum over the years. Thus, there 
are quite long series of some Himalayan species (from H. Stevens), while 
many common British species are either unrepresented or represented by 
only one or two examples. 

The nests have only been roughly sorted into families, and no catalogue 
has ever been made. The nests are stored in Tring cabinets, either loose in 
the plastic trays or in glass-topped boxes. 


The registers and the catalogues of the Museum collections fulfil quite 
separate purposes. The registers contain details of specimens, entered as 
they are acquired (or curated), and usually arranged in blocks of speci- 
mens received together. The catalogues contain details of specimens 
arranged in a systematic, or similar, order. 

A. G. Knox & M. Walters 186 Bull. B.O.C. 11 2 A 

The Old Catalogue 

The earliest extant list of the collection is a thick catalogue volume with 
pages watermarked '1813', compiled by Dr W.E. Leach. Each page was 
numbered and used for a different species, with the specimens listed in 
columns down the right-hand side. Some specimens were indicated by 
letters of the alphabet. A synonymy with references was given for each 
species. This volume is referred to as the Old Catalogue, and appears 
to have been in use from 1813 (or shortly afterwards) until about the 
commencement of the Vellum Catalogues. A note, probably by J.E. Gray 
or J.G. Children, referring to this Catalogue is to be found tipped in at the 
beginning of Vellum Catalogue volume 5. It explains some of the entries 
and indicates species that were wanting in 1824. 

The Vellum Catalogues 

Most of the entries from the Old Catalogue also appear in the more 
comprehensive Vellum Catalogues, which were mainly compiled by G.R. 
Gray. The paper in these volumes is watermarked 1832, 1833 and 1834. 
The Vellum Catalogues were not apparently maintained beyond 1837. 
Forty of the 44 volumes in the series are divided into 1 5 sets covering the 
major groups of birds. Within each set, the right hand pages are numbered 
consecutively, one for each species of bird, for which a partial synonymy, 
without references, was also given. Individual specimens were identified 
by different letters of the alphabet. The registration number 12.177b is 
therefore Vellum Catalogue, volume 12, species (page) no. 177, specimen 
2. The other 4 volumes (numbered 1—4) were used for British birds, and 
do not strictly belong with the remainder of the series. In the time of G.R. 
Gray, volumes 5-44 of the Vellum Catalogues were known as the General 
Catalogue, and the sets were identified with Roman numerals; reference 
to an entry took the form: xii 177b. 

The General Registers 

The main registers began in 1837 as a combined vertebrate series. 
These are referred to as the General Registers. Registration numbers 
originally comprised 4 groups of digits, the first 3 being the year, month 
and day of registration, and the last being the specimen number on that 
day, for example, 1842.5.17.16. Birds continued to be registered in the 
General Registers until 1853. A single Vellum register of birds was main- 
tained by G.R. Gray for 1837-8. It mainly consists of the same bird 
entries as are found in the General Registers for that period, but also has 
some which are not found there. 

The Aves Registers 

In 1854 the separate Aves (Bird) Registers were started, although bird 
skeletons were usually included with the rest of the vertebrates for several 
decades to come. Numbers in the Bird Registers follow the same format as 
described for the General Registers, until the 1940s, when the use of 3 
groups of digits was introduced: the year of registration, a number allo- 
cated to each collection, and the number of the individual specimen 
within that collection, e.g. 1945.64.202. This change took place in 
July 1943 for eggs, and January 1945 for other specimens. A few large 

Bull. B.O.C. 1 1 2A 187 BMNH bird collections 

collections were identified differently: e.g. 1949. WHI. 1.1-17450 for the 
Whistler collection; 1955. 6. N. 20. 1-4931 for the Gurney collection from 
Norwich Castle Museum and 1965.M. 1-1 9575 for the Meinertzhagen 

Separate registers were used for part or all of several very large collec- 
tions: Hume (3 volumes, 1885-95); Salvin & Godman (5 volumes, 1885- 
1913); Tweeddale (1887-92); Seebohm, Hargitt (1 volume, 1896-7); 
Simons (1902); Styan, McConnell (1 volume, 1907-22); Witherby, 
Ticehurst(l volume, 1934, 1941); Whistler (1949); Gurney, birds of prey 
(the original Norwich Castle Museum catalogue into which a NHM 
registration number prefix was placed before each catalogue number 
[1889] 1955); Meinertzhagen (1965); and Hewitt (1969). Some confusion 
was incurred by the use of separate registers, and duplicate numbers are 
often found. 

During the present century, most of the bird entries for the period 
1837-53 were copied out of the old General Registers , into a separate 
volume of the Bird Register which is now used at Tring. 

There are currently 29 volumes in the main Aves series, with a 30th in 
progress, and 17 volumes of special collections. Most run to 300-400 
pages, with about 50 lines per page. Up to the end of 1941, each Aves 
Register contains either one or two indexes to the donor and sellers of the 
collections listed therein. There is also a comprehensive index covering 
the period 1906—1920. A separate series of small, loose-leaf binders, 
listing donors/sellers (and their specimens) in alphabetical order, covers 
accessions from 1906 to the present. For the period prior to that, Sharpe 
(1906) gives an index, but it is not complete. 

Aves accessions for 1837—93 have been listed chronologically (and in 
part duplicated), one line to each collection, in a manuscript volume 
entitled 'Zoological Accession; Aves; 1837—1893'. This provides an 
additional means of tracing specimens without the need to scan the full 

The Skeleton Vellum Catalogues 

Separate Skeleton Vellum Catalogues (18 volumes), similar in layout to 
the Vellum Catalogues, were maintained from about 1844 (watermarked 
on the paper of the first 15 volumes; the last 3 are apparently later) 
through to the 1880s. Species numbers ran consecutively through the 
whole set, so volume numbers are not needed to locate entries, which take 
the form 944a. Most specimens also have General Register numbers. The 
catalogues appear to have been compiled initially between 1844 and 1846, 
probably for the bird part of Gray (1847). Some original entries do not 
bear General Register numbers, and some skeletal material remained 
unregistered until the 1950s, when all previously unregistered bones were 
registered. The old numbers are still found on many of the bones. 

Card indexes 

Separate card-indexes exist for the skeleton and spirit collections, and 
were apparently maintained until the 1 930s. The former runs to 9 drawers 
of 5 x 3 inch cards. The spirit index comprises 6 drawers, with a seventh 
containing miscellaneous entries. Both indexes bear cross-references to 

A. G. Knox & M. Walters 188 Bull. B.O.C. 1 12A 

R.B. Sharpe's Hand-list (Sharpe 1899-1909), and were started sometime 
after publication of that work. 

The Egg Register 

The register for eggs was separated gradually from the main skin series 
by 1916. Prior to that date, only the large Seebohm collection (1901) and a 
few others, from 1912 onwards, appear in the Egg Registers. There are 
now 5 volumes, with a sixth currently in use, as well as 3 catalogue 
volumes of the Munt collection (1941), into which Museum registration 
numbers have been inserted. In about the mid 1890s, Henry Seebohm 
compiled a 10 volume manuscript catalogue of the eggs in the Museum 
collection, apart, it seems, from those in the public galleries. It was never 
published, but formed the basis for Oates (1901-12). An alphabetical 
accessions register (of donors and sellers) for the egg collection was 
started in the 1950s. Further information on the egg collection (and 
details of the card-index to the collection) will be found elsewhere in this 

The Skeleton Register 

The register for skeletons was separated in 1 952. At about the same time, 
the entries for old skeletons were extracted from the Skeleton Vellum 
Catalogues and the General and Aves Registers in a separate volume. A few 
numbers were overlooked, but not many. 

The Nest, Spirit and Domestic Bird Registers 

The register for nests was separated in 1959 and that for anatomical 
specimens in 1969. Numbers in all these separate series follow the format 
described for the General and Bird Registers. 

Much of the nest collection is still unsorted and unregistered. Although 
new nests are given standard 3-part numbers, the old, previously unregis- 
tered nests are now allocated 2 groups of digits (collection and specimen), 
prefixed N (e.g. N257.3). Some nests previously given numbers in either 
the General or Aves Registers have been subsequently re-registered in this 
latter style. 

Between 1900 and 1920, a separate register was maintained for 
domestic birds, but only a few pages were ever used. 


Potential visitors to Tring should write to the Officer in Charge, stating 
the object of their proposed visit. Access is normally restricted to those 
undertaking original scientific research intended for publication. For 
such visits there is no charge. Work with commercial implications, 
including that of artists working on bird books, incurs bench charges or 
other fees. Visitors are encouraged to build bench fees into grant appli- 
cations where possible. The collections are not normally accessible to 
casual visitors, although open days are held from time to time. Loans 
are made only to recognised institutions, on the same basis as visitor 

Bull. B.O.C. 1 1 2A 1 89 BMNH bird collections 


Several catalogues have been compiled, of which Gray (1844-67, 1847, 
1863), Oates (1901-12), Sharpe & others (1874-98), Warren & Harrison 
(1 966-73) and Knox & Walters (MS) are the most important. In addition, 
there have been numerous guides to the specimens in the public galleries 
(often giving data), and detailed catalogues of individual collections 
received by the Museum. Some of the latter were published as books, and 
others as papers in journals. References are given above to surveys of the 
spirit and skeleton collections. 

Biographical and historical 

Much historical information, together with biographical sketches of 
many of the collectors and donors, can be found in Sharpe (1906). 
Additional material relating to authors and collections appears in each of 
the 3 volumes of the catalogue of type-specimens (Warren & Harrison 
1966-1973). Edwards (1870), Gunther (1975, 1980) and Steam (1981) 
give general histories of the Museum and many of the staff, while Miriam 
Rothschild (1983) describes in detail the life and work of her uncle, 
Walter, and his famous museum at Tring where the Bird Section is now 
housed. Although not written with the museum user specifically in mind, 
Mearns & Mearns (1988) provide biographies of a great many relevant 
authors and collectors. 


Drafts of the manuscript were read by Mr I.R. Bishop, Mr N.J. Collar, Mr G.S. Cowles, 
Dr C. Violani and Mrs F.E. Warr. We are grateful for their comments. 


Blandamer, J. S. & Burton, P. J. K. 1979. Anatomical specimens of birds in the collections 

of the British Museum (Natural History). Bull. Brit. Mus. (Nat. Hist.), Zool. ser. 34: 

Cherry-Garrard, A. 1922. The Worst Journey in the World, Antarctic 1910-1913. 2 vols. 

Clancey, P. A. 1984. Tring as an ornithological centre. Bokmakierie 36: 32-35. 
Clench, M. H. 1976. Possible pitfalls in museum specimen data. North American Bird 

Bander 1:20-21. 
Cocker, M. 1990. Richard Meinertzhagen: soldier, scientist & spy. (paperback) London. 
Conover, M. R. & Hunt, G. L. 1989. Interpreting the sex ratios of gulls using museum 

specimens. Colonial Waterbirds 12: 132-133. 
Edwards, E. 1870. Lives of the Founders of the British Museum. London. 
Foster, M. S. & Cannell, P. F. 1990. Bird specimens and documentation: critical data for a 

critical resource. Condor 92: 277-283. 
Gray, G. R. 1844-1867. List of the Specimens of Birds in the Collections of the British 

Museum. 5 parts in 8 vols. London. A 2nd edition of part 1 was issued in 1848. This 

work was never completed. 

— 1 847. List of the Osteological Specimens in the Collections of the British Museum. London. 

— 1863. Catalogue of British Birds in the Collections of the British Museum. London. 
Greenway, J. C. 1967. Extinct and Vanishing Birds of the World. 2nd edition. New York. 
Gunther, A. E. 1975. A Century of Zoology at the British Museum, through the Lives of two 

Keepers, 181 5-1 9 14. London. 

— 1980. The Founders of Science at the British Museum, 1 753-1900. Halesworth, Suffolk. 
Hall, B. P. 1974. Birds of the Harold Hall Australian Expeditions 1962-70. London. 
Hartert, E. & Venturi, S. 1909. Notes sur les Oiseaux de la Republique Argentine. Novit. 

Zool. 16: 159-267, pis. 2-3. 

A. G. Knox & M. Walters 190 Bull. B.O.C. 1 12A 

Knox, A. G. & Walters, M. P. (MS). Extinct and Endangered birds in the Collections of the 

Natural History Museum. 
Mearns, B. & Mearns, R. 1988. Biographies for Birdwatchers. London. 
Murphy, R. C. No date. Journal of the Tring trip, from the Letters and other Notes of Robert 

Cushman Murphy, 1932. Bound copies of letters, notes and cuttings, in the library at the 

NUM. Tring. 
Nicholson, E. M. & Ferguson-Lees, I. J. 1962. The Hastings Rarities. British Birds 55: 

Oates, E. W. (& Ogilvie-Grant, W. R.) 1901-1912. Catalogue of the Collection of Birds' Eggs 

in the British Museum (Natural History) . 5 vols. London. 
Parkes, K. C. 1989a. Sex ratios based on museum collections — a caution. Colonial 

Waterbirds 12: 130-131. 

— 1989b. Response to Conover and Hunt. Colonial Waterbirds 12: 220-221. 

Peters, J. L. & others. 1931-1987. Check-list of Birds of the World. 16 vols. Cambridge, 

Rothschild, M. 1983. Dear Lord Rothschild. Philadelphia & London. 
Sharpe, R. B. 1899-1909. A Hand-list of the Genera and Species of Birds. 5 vols. London. 
— 1906. Birds. Pp. 79-51 5 in, British Museum, The History of the Collections Containedin the 

Natural History Departments of the British Museum. Vol. 2. London. 

— & others. 1874-1898. Catalogue of Birds in the British Museum. 27 vols. London. 
Steam, W. T. 1981 . The Natural History Museum at South Kensington. London. 

Van Tyne, J. 1952. Principles and practices in collecting and taxonomic work. Auk 69: 

Warren, R. L. M. & Harrison, C. J. O. 1966-1973. Type-specimens of Birds in the British 

Museum ( Natural History ) . 3 vols. London. 
Wood, D. S. & Jenkinson, M. A. 1984. World Inventory of Avian Anatomical Specimens: 

geographical analysis. Norman, Oklahoma. 

— & Schnell, G. D. 1986. Revised World Inventory of Avian Skeletal Specimens, 1986. 

Norman, Oklahoma. 
— , Zusi, R. L. & Jenkinson, M. A. 1982a. World Inventory of Avian Skeletal Specimens, 

1982. Norman, Oklahoma. 
— , — , — , 1982b. World Inventory of Avian Spirit Specimens, 1982. Norman, Oklahoma. 

Addresses: Dr A. G. Knox, Buckinghamshire County Museum, Tring Road, Halton, 
Bucks, HP22 5PJ; M. Walters, Natural History Museum, Tring, Herts, HP23 6AP. 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1 992, 1 1 2A 1 91 M. LeCroy & F. Vuilleumier 

Guidelines for the description of new species in 


by Mary LeCroy & Fratifois Vuilleumier 

Received 5 June 1992 


This paper has been written because of our disappointment with many 
descriptions of new species of birds which we felt were not up to the high 
standards we should expect in modern avian systematic work. In an 
attempt to remedy this problem, we present in this paper a set of 
suggested guidelines, the use of which, we believe, would improve the 
current situation significantly. A preliminary version of this paper 
was presented in poster form at the XXth International Ornithological 
Congress in Christchurch, New Zealand (LeCroy & Vuilleumier 1990). 

After presenting the background and the data on the rate of new species 
descriptions in ornithology, we discuss the kinds of problems that exist, 
with descriptive examples, followed by a series of concrete and, we hope 
constructive, suggestions for future workers. 


About 35 years ago the catalogue of birds of the world at the species level 
appeared to be so nearly complete that Mayr (1957: 35) wrote: "I doubt 
that more than 20 new species will be discovered in the next ten years". 
Later, however, in view of the steady flow of descriptions of new species in 
the ornithological literature, Mayr (1971: 315) concluded that "the 
number of undescribed new species of birds is by no means nearly 
exhausted, contrary to my earlier predictions". 

Asking "Why have all these [avian] species been overlooked so long?" 
Mayr & Vuilleumier (1983: 229) wrote "One reason is that some of them 
are sibling species .... Another, and more important reason, is that some 
of these [new] species have exceedingly small ranges . . ., or are restricted 
to virtually inaccessible places visited only recently by ornithologists 
. . .". Continued exploration of remote, and hitherto nearly inaccessible 
places, has indeed resulted in the description of unexpectedly interesting 
species mostly from tropical areas (see also Diamond 1985). 

During the past 52 years ornithologists at the American Museum of 
Natural History (AMNH) in New York have published 6 reviews of new 
species of birds (Zimmer & Mayr 1943, Mayr 1957, Mayr 1971, Mayr & 
Vuilleumier 1983, Vuilleumier & Mayr 1987, Vuilleumier et al. this 
volume). These reviews can be undertaken because the AMNH houses 
the most complete bird collection in the world (about 830,000 skins and 
approximately 99% of the known 9000+ species) and offers the needed 
comparative material. Also, the rich library resources at AMNH permit 
us to have access to the vast majority of ornithological journals, even 
the most obscure and localized ones. The work done to prepare these 

M. LeCroy & F. Vuilleumier 192 Bull. B.O.C. 1 1 2A 

reviews has given us the opportunity to examine critically all new species 
descriptions published in the last 5 decades. 

Rate of new species descriptions 

In the 5 2 years from 1 93 8 to 1 990, 29 1 new binomina have been proposed in 
the literature, of which c. 55% are probably valid full species (including 
allospecies sensu Amadon 1966), 18% are subspecies, 13% are synonyms, 
1% are nomenclaturally invalid, 1% are hybrids and about 12% are 
species inquirendae. Over this period valid new species have thus been 
published at the rate of c. 3 species per year. This rate represents an 
annual increase of only 0.033% in the world's avifauna, an incredibly low 
figure. Probably in no other class of vertebrates are there so few as yet 
undescribed new species. 

Given such a small number of new species being described annually, it 
is all the more essential that ornithologists should publish descriptions 
that are uniform, precise and scientifically of the highest calibre, thus 
leading the way for equally high calibre descriptions of new species in 
other disciplines. Unfortunately, too many descriptions of new species in 
ornithology, even in the 1980s and the present day, remain substandard. 
Clearly this state of affairs needs urgently to be changed. 

The problem 

While writing a chapter on the species concept in ornithology, one of us 
(Vuilleumier 1976) reviewed 107 new species descriptions for the period 
1955 to 1974, and was struck by the relatively large number of poor 
descriptions of putative new species of birds. Later on, while preparing 
the last 3 reviews of new avian species (Mayr & Vuilleumier 1983, 
Vuilleumier & Mayr 1987, Vuilleumier et al. this volume) there was 
continued dismay at the mediocre quality of the work of some fellow 

Thus, Vuilleumier & Mayr (1987: 146) wrote: "The authors deplore 
the practice of some ornithologists to describe allegedly new species of 
birds without reference to a type specimen. Far too often, the description 
of new species of birds is published in very obscure journals, at times even 
in privately printed journals. New species of birds should be all described 
in widely read, easily accessible, and preferably refereed ornithological 
journals. This would certainly eliminate the necessity of spending much 
time tracking down names that eventually turn out to be nomina nuda or 
synonyms . . ." A few examples will illustrate what these authors meant 
and what we mean in the present paper. 

1. On 2 occasions, swallows (Hirundinidae) from Africa have been 
described as new on the basis of a single specimen obtained from flocks of 
migrants (Williams 1966, Fry & Smith 1985). Thus nothing is known of 
the breeding locality of these birds and in a group as difficult and wide- 
spread as the swallows, one cannot be sure that the proper comparisons 
have been made. 

2. In other cases, putative new species have been described, again with 
inadequate documentation, and in obscure publications that we have had 

Bull. B. O.C. 112A 193 Guidelines for new species 

much difficulty in finding, even in the comprehensive natural history 
libraries of the AMNH and the Museum of Comparative Zoology 
(MCZ). Thus Crax estudilloi was described in the Game Bird Breeders, 
Aviculturists, Zoologists and Conservationists' Gazette (see Vuilleumier & 
Mayr 1987: 140), which is not a professional ornithological journal, and 
Asthenes luizae was published in Volume 1 , number 1 , of Ararajuba (see 
Vuilleumier et al., this volume). Ararajuba is the journal of the Brazilian 
Society of Ornithology, and although there is no question of its scientific 
calibre, it is unfortunately not yet widely circulated outside Brazil, and an 
important new record could thus have been easily overlooked. 

3. In yet other instances, reading the description has proved almost 
impossible because of the language in which it was originally described 
(e.g. Vietnamese: Lophura hatinhensis — see Vuilleumier et al., this 

4. We have reviewed cases where the 'types' were live (cage birds) at 
the time of description or publication (e.g. Hypochera lorenzi and H. 
incognita — see Mayr & Vuilleumier 1983: 222). These birds belong to a 
notoriously difficult group where species limits are very difficult to draw, 
and the absence of designated type specimens means that the new species 
are impossible to evaluate. Frequently also, such captive birds fail to be 
preserved when they die (see Crax estudilloi — Vuilleumier et al., this 

5. A few years ago, the late Augusto Ruschi published no fewer than 4 
poorly crafted descriptions of alleged new hummingbird species from 
Brazil, leaving such a confusing trail of problems that the correct identity 
of these birds is only now beginning to be understood (Hinkelmann 

6. Perhaps the most striking example of inadequate presentation of a 
new species is illustrated by the recent description of Laniarius liberatus 
(Laniidae) from Somalia based chiefly on an analysis of DNA from blood 
samples and feather quills. The only known individual was caught in 
Africa, transported to Europe, and later transported back to, and released, 
in Africa, but, incredibly, not where it had been originally captured 
(Smith et al. 1991). Furthermore, this case is interesting because it 
received extensive coverage, including notes in Trends in Ecology and 
Evolution (Hughes 1992a,b, Peterson & Lanyon 1992), a piece in BBC 
Wildlife (Scott 1991), 2 letters in Oryx (Ansell 1992, Bourne 1992) and 
even a long article in the New York Times by Carol Kaesuk Yoon in the 
Science Section of 28 April 1992. 

This specimen was doubly wasted. Its survival in a strange area after a 
year in captivity is highly unlikely and its ability to find a mate and 
reproduce is even more unlikely. Thus it was returned to the wild to die. 
Nor is there now any voucher specimen for the sample of DNA or a type 
specimen to serve as a standard of reference for the application of the new 
name. Believing in the good faith of the authors is not sufficient; it is a 
basic tenet of the scientific method that the availability of documentation 
and specimens is essential to permit others to assess the quality and 
accuracy of a scientist's work. That only one individual was seen in no way 
implies that the 'new' species is on the verge of extinction, or even rare. 
We highly recommend a recent article on the importance of collections 

M. LeCroy & F. Vuilleumier 194 Bull. B.O.C. 1 1 2A 

and collecting, which was in fact published before the appearance of the 
description of the shrike (Winkler et al. 1991). 

We feel that the standards of species description in ornithology, instead 
of improving, may be declining. Even professionally trained ornithologists 
are publishing bad descriptions of putative new species, while too many 
untrained ornithologists publish 'new' species in very local journals. 

We wish to emphasize here that there are, and have been, excellent 
descriptions of new species in the literature. As models for good descrip- 
tions of new species of birds (without implying a judgment on the validity 
of the new taxon) we can cite those of Stachyris latistriata (Gonzales & 
Kennedy 1990) from the Philippines, Meliphaga hindwoodi (Longmore & 
Boles 1983) from Australia, Pyrrhura orcesi (Ridgely & Robbins 1988) 
from Ecuador, and Cercomacra manu (Fitzpatrick & Willard 1990) from 
Peru. We congratulate the authors of these and other similarly good 
descriptions, and suggest that these descriptions ought to serve as models 
for other workers. 

In many countries where amateur ornithologists are numerous (Europe, 
USA), committees of specialists examine critically each sight record of a 
bird species allegedly identified as rare or new for that country. On the 
basis of the merit of each case, some of these records are accepted but 
others are simply rejected. We do not advocate the establishment of an 
international committee of reputable avian systematists who would simi- 
larly review critically each new species description, but we feel that high 
standards must be adhered to. Instead we present below deliberately 
explicit guidelines in order to help raise standards in the future. However, 
the clear distinction between species descriptions and discussions of 
species concepts first needs emphasising. 

One of us (Vuilleumier 1976: 50) remarked earlier that new species of 
birds had very often been described by authors according to a morpho- 
logical or typological species concept. At the time, Mayr's (1963b) bio- 
logical species concept (and see Mayr 1982) was probably accepted by 
these authors, as opposed to some today (e.g. Cracraft 1983, McKitrick & 
Zink 1988) who prefer a phylogenetic one. All these concepts, and their 
relevance to systematics, classification, and speciation analysis, have been 
admirably covered by Haffer (1986, 1990) and need not be discussed 

In the earlier instalments on new avian species, although judgment was 
passed on the validity of the new species of birds we reviewed, judgment 
was not passed on the species concept represented by each of those new 
species. Nor is this so in the present article, our goal being only to express 
our concerns about the standards of description of new species, without 
reference to species concepts. 

The International Code of Zoological Nomenclature 

The starting point for professional practice is clearly the International 
Code of Zoological Nomenclature (ICZN). J. Chester Bradley in the 
Preface to the first edition of the ICZN (1961) wrote the following: 

"Like all language, zoological nomenclature reflects the history of 
those who have produced it, and is the result of varying and conflicting 

Bull. B.O.C. 112A 195 Guidelines for new species 

practices .... Ordinary languages grow spontaneously in innumerable 
directions; but biological nomenclature has to be an exact tool that will 
convey a precise meaning for persons in all generations." 

The rules, recommendations and code of ethics of the ICZN (3rd ed, 
1985, or subsequent editions) should be followed in the description of all 
new species of birds. It is important to point out in particular that: 

(a) The Code does not infringe upon taxonomic judgement, or 
determine the rank to be given a population, but that 

(b) The Code does promote stability and universality in the scientific 
names of animals, including birds, and provides, in the words of the Code, 
"a Name-Bearing Type" which is the specimen that provides an "objec- 
tive standard of reference whereby the application of the name of a taxon 
can be determined". In the original description of a new species-level 
taxon this may be either: 

(i) a holotype: a single specimen (or the single specimen) designated to 

bear the proposed name, or 
(ii) a syntype: each specimen in the series mentioned in the description, 
when no holotype is designated. 

Guidelines on what to publish 

We list below the minimal number of items that we feel are absolutely 
necessary for inclusion to create a good description of a new species of 

1 . Holotype or syntypes should be designated. To facilitate future com- 
parisons and permit measurements to be made, we feel strongly that it is 
imperative that the type(s) be specimen material and not illustration, bits 
of feathers, or blood or tissue samples. The latter can be useful in many 
ways, but are no substitute for a type specimen, only additional evidence 
(see below). Additional specimens in a type series are highly desirable 
because they illustrate population variability. 

2. Minimal information should include the catalogue number and the 
name of the institution where the type is deposited, the sex and age of 
the type specimen(s), the collecting locality in as much detail as 
possible, including coordinates and altitude, the date of collection, 
name(s) of collector(s), measurements and a detailed word description of 
the type(s). 

3. Desirable additional information that may be the necessary basis 
upon which to judge the validity of the new species includes voice record- 
ings, blood samples, tissue samples, anatomical specimens, notes on 
behaviour, ecology, etc. 

4. The etymology and gender of the name proposed must be given. 

5. Explanation should be given as to why the new species is included in 
a given existing genus, or why it is placed in a new genus. Comparisons 
should be detailed, and substantiated with adequate material such as 
figures or tables, and maps. 

6. Comparisons made should be the appropriate ones; similar and/or 
related sympatric and allopatric forms should be compared in detail with 
the new species, maps should be included to illustrate the geographical 
relationships with precision. 

M. LeCroy & F. Vuilleumier 196 Bull. B.O.C. 1 12A 

7. Discussion of the biogeography of the genus in which the new taxon 
is placed is highly desirable, thus identifying the eco-geographic context 
of the new species within or among previously known species. Whether 
the new species is geographically disjunct, or is an allospecies (sensu 
Amadon 1966) or is an isolated species, should be discussed. 

8. Why the new taxon, if allopatric, is a new species and not a new 
subspecies and what species concept is being followed in this instance 
should be explained. 

Publishing a proposed name 

New species of birds should be described in refereed journals whose 
editors are thoroughly familiar with the proper format for the description 
of a new taxon and with the ICZN. This will ensure that the necessary 
information for correct description is included and also will bring the 
proposed new taxon readily to the attention of the scientific community. 
It would be the responsibility of the editor to verify that the new species 
description submitted for publication conforms to the format advocated 
here, and which we hope can be accepted universally. 

Although it is perfectly understandable that authors of new species 
should wish to publish such descriptions in their native language, today 
the lingua franca of science is English. Nearly all ornithologists can read 
English, even if they do not speak it. Hence a publication in the English 
language, or at least a thorough summary in English, would ensure, and 
to the author's benefit, that the description of a newly proposed taxon 
can be made available to as wide an international audience as possible. 
We strongly condemn the practice of some ornithologists of publishing 
new descriptions in books or catalogues, where they may be easily 

Deposition of type(s) 

Because types are so important in basic systematic work, several rules 
must be followed for their true designation. They include: 

1 . The type(s) should be deposited in a recognized museum with good 
facilities for proper permanent storage of specimens and with an interest 
taken in care and preservation of type specimens on the part of profession- 
ally trained curators. It is of little use to anyone to keep the type in a 
private collection. 

2. The type(s) should be labelled in a way that makes the special status 
of a type specimen immediately apparent; the type(s) should preferably 
be kept separate from the general collection. 

3 . Bibliographic reference to the published description and the proposed 
name should be clearly written on the label. 

4. Since types are such crucial and essential repositories of systematic 
and biological information, yet are probably not loaned safely because of 
the vagaries of modern mails, they should be housed in institutions that 
can be visited relatively easily by ornithologists. 

Bull. B.O.C. l\2A 197 Guidelines for new species 


We agree with Peterson & Lanyon (1 992) that the best kind of new species 
description is a detailed one which includes a variety of types of infor- 
mation, backed up by type specimens. Interestingly, included in the New 
York Times article mentioned above is a list of the minimal items of 
information needed for an adequate description, from sources provided 
by Richard C. Banks of the U.S. Fish and Wildlife Service, Washington, 
D.C. It is most gratifying to see that Banks' list conforms in all ways with 
our own views, as expressed in this paper. 

Conservation cannot proceed without detailed knowledge of avian 
diversity, and this can only be acquired by judicious sampling of popu- 
lations and careful systematic analysis of collections. Given the current 
rate of habitat destruction, we wish to note here that conservationists who 
are against such sampling are jeopardizing their own efforts by hampering 
the acquisition of vital knowledge before it is too late. 

As Mayr pointed out 30 years ago, avian biologists, including amateurs, 
have been leaders in several fields of biology in the past; in systematics this 
leadership could be accomplished because of the "completeness of the 
knowledge of birds" and especially because "most bird species are not 
merely known but also abundantly sampled from throughout their range" 
(Mayr 1963a: 30). However, it is becoming increasingly apparent as habi- 
tats are being destroyed at an alarming rate, that very many bird species 
are still insufficiently sampled and incompletely known and that the avail- 
ability of discerningly collected specimens is more critical now than ever 
before. If we are to retain this status of leadership in the specialised branch 
of systematics which consists of describing new species-taxa, ornithologists 
must practice self-discipline and must follow a minimum number of rules. 
We hope that ornithologists who intend to describe new species of birds in 
the future will find our guidelines in this paper useful. If we want to avoid 
ridicule, we must avoid the kind of work that we still see too often 
published, even by colleagues who should know better. 


We are grateful to James Monk for his constructive criticisms of a draft of this paper and we 
thank Elizabeth De Jesus for typing the manuscript. 


Amadon, D. 1966. The superspecies concept. Syst. Zool. 15: 245-249. 

Ansell, W. F. H. 1992. To collect or not to collect — a conservation issue? Oryx 26: 119. 

Bourne, W. R. P. 1992. Of shrikes, shrews and storm-petrels. Oryx 26: 119-121. 

Cracraft, J. 1983. Species concepts and speciation analysis. Pp. 159-187 in R. F. Johnston 

(ed.), Current Ornithology. Vol. 1. Plenum Press, New York. 
Diamond, J. M. 1985. How many unknown species are yet to be discovered? Nature 315: 

Fitzpatrick, J. W. & Willard, D. E. 1990. Cercomacra manu, a new species of antbird from 

southwestern Amazonia. Auk 107: 239-245. 
Fry, C. H. & Smith, D. A. 1985. A new swallow from the Red Sea. Ibis 127: 1-6. 
Gonzales, P. C. & Kennedy, R. S. 1990. A new species of Stachyris babbler (Aves: 

Timaliidae) from the Island of Panay, Philippines. Wilson Bull. 102: 367-379. 
Haffer, J. 1986. Superspecies and species limits in vertebrates. Zeitschr. Zool. Syst. 

Evolutionsforsch. 24: 169-190. 
— 1990. Ornithologists and species concepts. Proc Int. 100 DO-G Meeting, Current Topics 

Avian Biol., Bonn 1988: 57-60. 

M. LeCroy & F. Vuilleumier 198 Bull. B.O.C. 1 12A 

Hinkelmann, C. 1988. Comments on recently described new species of hermit 

hummingbirds. Bull. Brit. Orn. CI. 108: 159-169. 
Hughes, A. L. 1 992a. Avian species described on the basis of DN A only. Trends Ecol. Evol. 

7: 2-3. 

— 1992b. Reply from Austin Hughes. Trends Ecol. Evol. 7: 168. 

International Code of Zoological Nomenclature. 1961. 1st ed. International Trust for 

Zoological Nomenclature, London. 
International Code of Zoological Nomenclature, 1985. 3rd ed. International Trust for 

Zoological Nomenclature, Univ. California Press, Berkeley. 
LeCroy, M. & Vuilleumier, F. 1990. Guidelines for the description of new species in 

ornithology. [Abstract.] Acta XXCongr. Internat. Ornithol. (Suppl.): 378. 
Longmore, N. W. & Boles, W. E. 1983. Description and systematics of the Eungella 

Honeyeater Meliphaga hindwoodi, a new species of honeyeater from central eastern 

Queensland, Australia. Emu 83: 59-65. 
McKitrick, M. C. & Zink, R. M. 1988. Species concepts in ornithology. Condor 90: 1-14. 
Mayr, E. 1957. New species of birds described from 1941 to 1955.^. Orn. 98: 22-35. 

— 1963a. The role of ornitholgical research in biology. Proc. XII Ith Internat. Ornithol. 

Congr.: 27-38. 

— 1963b. Animal Species and Evolution. Cambridge, Massachusetts, Harvard Univ. 


— 1971. New species of birds described from 1956 to 1965. J. Orn. 112:302-316. 

— 1982. Processes of speciation in animals. Pp. 1-19 in C. Barigozzi (ed.), Mechanisms of 

Speciation. Alan R. Liss, New York. 
Mayr, E. & Vuilleumier, F. 1983. New species of birds described from 1966 to 1975.^. Orn. 

Peterson, A. T. & Lanyon, S. M. 1992. New bird species, DNA studies and type specimens. 

Trends Ecol. Evol. 7: 167-168. 
Ridgely, R. S & Robbins, M. B. 1988. Pyrrhura orcesi, a new parakeet from southwestern 

Ecuador, with systematic notes on the P. melanura complex. WilsonBull. 100: 173-182. 
Scott, K. 1991. World first: bird survives baptism. BBC Wildlife 9 (8): 534. 
Smith, E. F. G., Arctander, P., Fjeldsa, J. & Amir, O. G. 1991. A new species of shrike 

(Laniidae: Laniarius) from Somalia, verified by DNA sequence data from the only 

known individual. Ibis 133: 227-235. 
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Genermont & M. Lamotte (eds.), Les Problemes de I'Espece dans le Regne Animal. Tome 

I. Soc. Zool. France, Mem. no. 38. Paris. 
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Williams, J. G. 1966. A new species of swallow from Kenya. Bull. Brit. Orn. CI. 86: 40. 
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Zimmer, J. T. & Mayr, E. 1943. New species of birds described from 1938 to 1941. Auk 60: 


Address: Francois Vuilleumier & Mary LeCroy, American Museum of Natural History, 
Department of Ornithology, Central Park West at 79th Street, New York, NY 
10024-5192, U.S.A. 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 199 H. Lohrl & E. Thaler 

Behavioural traits as an aid to solving taxonomic 


by Hans Lohrl &. Ellen Thaler 

Received 30 April 1992 

Until the end of the last century taxonomists relied entirely on morpho- 
logical data obtained from skin collections. An article by Whitman (1898) 
entitled "Animal behavior" was the first publication to appear on this 
subject and accordingly attracted much attention. Later, the behaviour of 
the Anatidae was studied by Heinroth (1910), and thereafter, especially 
from 1 927 and 1 930 onwards, Lorenz published numerous papers, includ- 
ing (1941) reporting a comparative study of the behavioural patterns of 20 
different species of the Anatinae, which considered the behaviour of 
females, males and young birds separately. 

The methods employed in Lorenz's studies on tame ducks living under 
natural conditions were of a pioneering nature. Thereafter, all behavioural 
studies were carried out on birds kept under natural conditions, or by 
observing wild birds from a hide. Subsequently the literature on ethology 
has been voluminous. 

However, in order to derive a taxonomic interpretation from behav- 
iour, it has first to be decided which aspects of behaviour from which 
functional system are suitable for this purpose. Obviously of little value 
are behavioural components that are strongly influenced by abiotic and 
biotic environmental factors (such as climate, temperature, day length, 
form of vegetation, food supplies etc). Furthermore, we know that certain 
ecotypes, such as those of aquatic birds and birds of the high mountains, 
or those living in rocky regions, invariably exhibit convergent specific 
adaptations to their particular environment. We are, therefore, limited to 
behavioural traits that are influenced to a minimal degree by the environ- 
ment, e.g. nest building, brood care, nestling behaviour, and to some 
extent also social behaviour and certain calls. All aspects of behaviour 
connected with obtaining food, on the other hand, on account of their 
high susceptibility to adaptive radiation, should be treated with caution. 
Nevertheless, certain elements of such behaviour can be extremely 
informative, such as the use of the foot in manipulating food, or other 
special adaptations. The greater the number of functional systems for 
which behavioural differences can be demonstrated, the more 
informative are these results for our present purpose. 

Behavioural comparisons in the Regulidae 

The classification of the family Regulidae recommended by Sibley & 
Ahlquist (1985) was not entirely acceptable. Additional uncertainties 
arose from a re-evaluation of the genetic differentiation of the American 
twin species Regulus satrapa and R. calendula by Ingold et al. (1988). On 
the basis of their investigations the authors claimed that the 2 species are 
"not closely related", which, as they pointed out, had already been 

H. Lohrl & E. Thaler 


Bull.B.O.C. 112A 

Breeding and other behaviour in 4 species of Regulus to demonstrate the many differences in 

R. calendula 

R. regulus 


R. ignicapillus 



R. satrapa 



R. calendula 

Social behaviour 

in migratory and 

wintering flocks 
contact sleep 




no contact sleep 


territorial; hanging 




Nesting material 

very fine 



also stalks and 


no courtship feeding 

courtship feeding 

courtship feeding 

no courtship 

Nestling nutrition 

mainly collembola, 
tiny arthropods 

soon larger prey 

same as ignicapillus 

same as ignicapillus 


down on head 



no down 

Nestling period 

(days): 22 




Nestling behaviour 

huddle together after 

leaving nest; 
return to nest for 1-2 




do not huddle after 
leaving nest; 
do not return to 

Territorial song 

typical for Regulidae 



atypical in 
frequency and 

claimed by Mayr & Short (1970). Assuming that the 2 species reached 
the American continent at different times, Ingold et al. concluded that the 
"DNA data suggest that the Ruby-crowned Kinglet [R. calendula] is the 
most recent arrival". If, however, the 2 species are judged on the basis 
of their behaviour, and if they are compared in a similar way with the 
European twin species R. regulus and R. ignicapillus, it is impossible to 
agree with Ingold etal.'s conclusion (see Thaler 1988) (Table 1). E. Mayr 

Bull. B.O.C. 112A 201 Solving taxonomic problems 

(pers. comm. 1988) also expressed his doubts: "surely this Ruby- 
crowned kinglet arrived in North America long before the Gold-crowned 
[jR. satrapa], not the reverse . . .". 

The most striking differences in behaviour between calendula and the 
other 3 species are seen, for example, in connection with display (Fig. 1), 
which, although always species-specific, only in calendula differs entirely 
from the Regulidae pattern (Thaler 1988), as also in its song (see also 
Mayr 1956). In addition only in calendula do some of the first-year males 
regularly show delayed maturation plumage (i.e. may moult into a second 
juvenile plumage) (Thaler in press), whereas the other Regulidae species 
avoid intraspecific aggression in their first year by 'behavioural mimicry' 
(i.e. concealing the orange in their crown and behaving like females) 
(Thaler 1979, 1990). The complete absence of nestling down in calendula 
probably further differentiates it from other Regulidae. Thaler (1988) 
showed that ignicapillus has more primitive behavioural patterns than 
regulus and is most probably the common ancestor of all Regulidae. It 
would seem therefore that calendula has evolved from ignicapillus and in 
isolation in America has since acquired the differentiating characteristics 
which separate it from satrapa, the later arrival which has differentiated 
little as yet. 

Behavioural traits of Leptopoecile sophiae 

Although Severtzov's Tit Warbler Leptopoecile sophiae is no unfamiliar 
species (see Ali & Ripley 1971/2, Dementiev & Gladkov 1954), our 
knowledge of its behaviour is incomplete and its systematics still await 
clarification. Nicolai & Wolters (1971) placed Leptopoecile, presumably 
on account of its minute size, among the Regulidae, in whose vicinity it 
was also placed by Hartert (1916) and Stresemann et al. (1937). Schafer 
(1938) placed it close to the tits, particularly to the Aegithalidae. The 
genus was not considered by Sibley & Ahlquist (1985). One of us has kept 
4 pairs of Leptopoecile sophiae in aviaries since 1990, and it seems that 
Leptopoecile had not previously, at least for any length of time, been kept 
in aviaries. A wealth of unknown behavioural details was to be expected 
and was observed. Their social behaviour appeared highly developed and 
ritualized, and the existence of social courtship behaviour and group 
'helpers' can be assumed. Leptopoecile, like Regulus, feeds on arthropods 
and, because it inhabits thickets, they also appear to have certain similar 
foraging strategies, since these are influenced by the environment. Never- 
theless, when carefully observed they prove to differ fundamentally in 
feeding habits. Leptopoecile uses its feet (Fig. 2), tending to a similarity 
with the Aegithalidae (cf. e.g. Aegithalos concinnus — Lohrl 1985), with 
which they also share social behaviour and nest-building characteristics 
(Table 2). 

Behavioural comparisons between the Sittidae and Paridae 

The nuthatches (Sittidae) and the tits (Paridae) provide good examples of 
the fact that purely morphological studies do not necessarily yield 
unequivocal results. Hartert (1910-1922), convinced that these 2 families 

H. Lohrl & E. Thaler 


Bull. B.O.C. 11 2A 

Figure 1. Threatening behaviour of (A) Regulus tgnicapUlus, (B) R ^pillus and R. 
satrapa, (C) R. regulus and (D) R. calendula. Adapted from Thaler-Kottek (1986). 

Bull.B.O.C. 112A 


Solving taxonomic problems 

Figure 2. Severtzov's Tit Warbler Leptopoecile sophiae manipulating a moth by use of the 

Breeding and other behaviour comparisons in Leptopoecile sophiae, Regulidae and 


Leptopoecile sophiae 



Social behaviour 

year-round social or group 
territoriality ('helpers'?) 

Nesting site, type of nest 

in bushes, oven-shaped nests 


no courtship feeding 




uncovers hidden food 

Feeding strategies 

uses feet, even clamps prey; 
searches ground by 
scattering litter and 
turning over leaves 


clicking, purring 

seasonally monogamous 

in trees, bowl-shaped, 
hanging nests, opening 

courtship feeding in 
ignicapillus and satrapa 


eats visible food only 

year-round social or group 
territoriality ('helpers') 

in bushes and trees, oven- 
shaped nests, supported or 

no courtship feeding 

uncovers hidden food 

feet never used; prey 'killed' uses feet; does not search 
by banging ground 

pure, high-pitched notes clicking, purring 

H. Lohrl & E. Thaler 204 Bull. B.O.C. 1 1 2A 

were closely related, placed the Paridae immediately after the Sittidae. A 
similar view was held by Vaurie (1959), who brought the Paridae even 
closer to the Sittidae by placing the latter as a subfamily, Sittinae, in the 
Paridae. However, this sequence was again completely altered on the 
basis of purely morphological considerations by Wolters (1975—1982), 
in his principal publication. For him, the Sittidae and Paridae were 
unrelated and far removed from one another. Between them he placed, for 
example, the extensive families of Nectariniidae, Estrildidae, Ploceidae 
and Emberizidae, and even the Sylviidae — as a separate family — are 
considered before the Paridae. 

The distance placed between the nuthatches and tits by Wolters clearly 
shows that even the most conscientious examination of morphological 
characteristics of dead animals is, on its own, an inadequate means of 
arriving at reliable systematic conclusions. Following DNA hybridization 
studies, Wolters (1983) did in fact modify his views, placing the Sittidae 
nearer to the Paridae again. 

Table 3 gives a comparison of the breeding and feeding habits of tits 
and nuthatches, based on detailed observations (Lohrl 1958, 1964, 1974, 
1991). The behavioural traits cited are partially dependent on breeding 
site and environment. Inhabitants of tropical and subtropical regions 
gather no food reserves (e.g. Velvet-fronted Nuthatches Sitta frontalis 
and probably the African tit species). In Europe the Great Tit Parus 
major and the Blue Tit P. caeruleus do not lay up stores, but compensate 
for winter population losses resulting from food shortage by producing 
large numbers of offspring. 

Behavioural traits of Tichodroma muraria 

The Wallcreeper Tichodroma muraria was formerly grouped with the 
treecreepers (Certhiidae), e.g. by Hellmayr 1903, Hartert 1910-1922, 
due to false interpretation of their similar bills. Later it was considered as 
a subfamily of the Sittidae (Vaurie 1959, Peters 1967, Sibley & Ahlquist 
1985) or even to be a distinct family (Voous 1977, Wolters 1975-1982). 

Behavioural traits can only be taken as evidence of possible affinities if 
they are not ecological adaptations. In this particular specialist of high 
mountain regions, however, most of its characteristic movements are 
adaptations to its habitat. This is also true of its manner of seeking food 
and its flight. The exceptionally large wings permit the bird to exploit 
updraft to transport it from the depths of gorges into the upper regions. In 
searching for a behavioural trait of the Wallcreeper that is with certainty 
not an adaptation to its habitat, the possibility of a close affinity to the 
nuthatches was suggested by their similar attitudes in inter- and intra- 
specific conflicts; both the Wallcreeper and nuthatches adopt the same 
threatening posture, letting their wings hang and holding their tails erect 
(Fig. 3). Such a posture is seen in neither tits nor treecreepers. In 
addition, during the breeding season a gliding form of flight is observed in 
all nuthatches and also in the Wallcreeper (Lohrl 1988). 

On the other hand, other forms of nuthatch behaviour, such as the way 
they handle food or, with the exception of tropical species, the laying-up 
of food stores, distinguish nuthatches from the Wallcreeper so clearly that 

Bull.B.O.C. 112A 


Solving taxonomic problems 

Comparison of behavioural traits of tits (Paridae) and nuthatches (Sittidae) (but see text) 


Breeding behaviour 

Feeding behaviour 

behavioural traits 

Nests in holes in trees, the holes enlarged to the required size 

where necessary. In larger holes the nesting space is partially 

filled with moss or wood. Cracks in the walls are stopped up 

with nesting material. 

Nesting material: moss, wool, feathers, pieces of bark. 

Eggs covered up with nesting material before incubation begins. 

Incubation of completed clutch can be postponed by as much as 

a week in periods of bad weather. 

Courtship feeding of female by male during nest-building 


Young fed by both parents. 

Long nestling period: 18-23 days. 

Summer: insects and spiders. 

Winter: spiders, insects and plant diet. 

Sometimes lay up stores. Hidden food reserves sometimes 

covered up. Seeds sometimes deposited on a branch before 


Wing flicking when excited. 

Distraction behaviour: droops, waves and spreads wings and 





Breeding behaviour 

Feeding behaviour 

Incubation 12—15 days. 
Defends brood by complex 
defence behaviour: hissing, 
flapping wings against sides 
of hole, bill-snapping. 

Breaks up hard food items 
while gripping with toes. 

Incubation 15—18 days. 
Reduces size of entrance to 
nest with mud, for security. 

Breaks up hard food by 
pushing it into cracks and 
hammering with bill. 

a separate family for Tichodroma, which should follow the Sittidae, seems 
to be ethologically justified. 

Behavioural traits of Siphia strophiata 

The affinities of the small flycatchers, which are common species in Asia, 
present special problems. In his generic revision of the Muscicapini 
Vaurie (1953) divided them mainly between the genera Ficedula, Niltava 
and Muscicapa. Originally, most of them had been placed in the genus 
Muscicapa — a classification still widely adhered to (e.g. by Ali & Ripley 
1972, Etchecopar & Hue 1983). Earlier taxonomic studies of these 
species, apart from morphological peculiarities or a comparison of habitats, 
were restricted to the observation that flycatchers "catch insects in the air", 
which holds equally for all 77 species treated by Vaurie, while even today, 

H. Lohrl & E. Thaler 


Bull.B.O.C. 11 2A 


Figure 3. Threatening behaviour of the European Nuthatch Sitta europaea (top) and 
Wallcreeper Tichodroma muraria (bottom). 

few details of their breeding biology have been described. The accurate 
observation of differences in behaviour under species-adequate aviary con- 
ditions is both possible and rewarding. The Orange-gorgeted Flycatcher 
Siphia strophiata is a good example, as decribed below. 

The systematic position of S. strophiata is still controversial: in Hartert 
(1910-1922) it was termed Muscicapa strophiata and Vaurie (1953) con- 
sidered it "appears to be not too distantly related to the Ficedula group". 
His decision was made mainly on the basis of morphological character- 
istics, although he was open to a consideration of such behavioural traits 
as were available. 

Observations on S. strophiata kept in cages and aviaries over a con- 
siderable number of years revealed a most unusual method of obtaining 
food, otherwise seen mainly in limicoles (Lohrl 1992). By means of 
vibrating foot movements the birds shake the twigs on which they are 
perching and thus mobilise at the surface hidden prey. This is an innate 
foraging movement, since it was observed not only in several im- 
ported mature birds, but also in a young, aviary-hatched, hand-reared 
individual that had subsequently been isolated and thus had received no 
'instruction' from an adult. S. strophiata is the only species of flycatcher 
so far known to use this method, and presumably thus secures itself an 

Bull. B.O.C. 112A 207 Solving taxonomic problems 

advantage over other species. It was not only this unusual method of prey- 
catching that raised the suspicion that this was not a 'normal' Muscicapa 
or Ficedula species. The bird's song resembles rather that of the 
Bluethroat Luscinia svecica, or the Robin Erithacus rubecula, and its fre- 
quent tail twitching is also seen in the Robin. The impression that its 
behaviour hardly resembles that of a flycatcher remained unaltered over 
the 8 years during which one of us observed a number of these birds; no 
visiting ornithologist thought these birds were a species of flycatcher, and 
most of them guessed that they were a species of thrush. 

The removal of this species from the other flycatcher genera and its 
renaming (Wolters 1975-1982) as Siphia strophiata is fully justified from 
the ethological point of view. 


Behavioural patterns can be a useful supplementary help in clarifying some 
taxonomic questions. It seems that even very advanced techniques such as 
DNA hybridization are not entirely immune to subjective interpretation 
or free from errors. Only by considering the bird as a whole are we in a 
position to ask meaningful questions . Although it may be an exciting idea to 
take apart such a complex organism and then to attempt to reassemble it as 
if it were a puzzle, this involves the danger of losing sight of the overall 
picture, and perhaps also our feeling for the harmony of the whole. 


AH, S. & Ripley, S. D. 1971, 1972. Handbook of the Birds of India and Pakistan, together with 

those of Nepal, Sikkim, Bhutan and Ceylon. Vols. 6-8. Bombay. 
Dementjev, G. P. & Gladkov, N. A. 1954. Birds of the Soviet Union. Vol. 6. Moscow. 
Etchecopar, R. D. & Hue, F. 1983. Les Oiseaux de Chine — Passereaux. Paris. 
Hartert, E. 1910-1922. Die Vogel der Palaarktischen Fauna. Berlin. 
Heinroth, O. 1910. Beitrage zur Biologie, namentlich Ethologie und Psychologie der 

Anatiden. Verh. Intern. Ornith. Congr. Berlin: 615. 
Hellmayr, C. E. 1903. Das Tierreich 18, Aves: Paridae, Sittidae und Certhiidae. Berlin. 
Ingold, J. L., Weight, L. A. & Guttmann, S. 1. 1988. Genetic differentiation between North 

American Kinglets and comparisons with three allied Passerines. Auk 105: 386-390. 
Lohrl, H. 1958. Das Verhalten des Kleibers (Sitta europaea caesia Wolf). Z. Tierpsychol. 15: 


— 1964. Verhaltensmerkmale der Gattungen Parus (Meisen), Aegithalos (Schwanzmeisen), 

Sitta (Kleiber), Tichodroma (Mauerlaufer) und Certhia (Baumlaufer). J. Ornith. 105: 

— 1974. Die Tannenmeise. Neue Brehm-Biicherei 472. Wittenberg-Lutherstadt. 

— 1985. Die Rostkappenschwanzmeise (Aegithalos concinnus). Gef. Welt 109: 334—335. 

— 1 988. Etho-6kologische Untersuchungen an verschiedenen Kleiberarten (Sittidae). Bon. 

Zool. Monogr. 26: 1-208. 

— 1991. Die Haubenmeise, Parus cristatus. Neue Brehm-Biicherei 609. Wittenberg- 


— 1992. Siphia strophiata, der Zimtfleckschnapper. Tropische Vogel 13: 3-8. 
Lorenz, K. 1927. Beobachtungen an Dohlen. J. Ornith. 75: 511-519. 

— 1931. Beitrage zur Ethologie sozialer Corviden. J. Ornith. 79: 67-127. 

— 1932. Betrachtungen iiber das Erkennen der arteigenen Triebhandlungen der Vogel. J. 

Ornith. 80: 50-98. 

— 1941. Vergleichende Bewegungsstudien an Anatinen.X Ornith. Erg. Bd. Ill: 194-293. 
Mayr, E. 1956. Gesang und Systematik. Beitr. Vogelkunde 5. 

Mayr, E. & Short, L. L. 1970. Species Taxa of North American Birds. Cambridge, Mass. 

Publ. Nuttall Orn. Club 9. 
Nicolai, J. & Wolters, H. E. 1971 . Vogel in Kafig und Voliere. Vol. 2. Aachen. 
Peters, J. L. 1967. Check-list of Birds of the World. Cambridge, Mass. 

H. Lohrl & E. Thaler 208 Bull. B.O.C. 1 1 2A 

Schafer, E. 1938. Ornithologische Ergebnisse zweier Forschungsreisen nach Tibet. J. 

Ornith. 86, Sonderheft. 
Sibley, C. G. & Ahlquist, J. E. 1985. The Phylogeny and Classification of the Passerine 

Birds, based on Comparisons of the Genetic Material DNA. Acta XVIII. Congr. Int. 

Orn. Moscow: 83-1 21. 
Stresemann, E., Meise, W. & Schonwetter, M. 1937. Aves Beickianae. Beitrage zur 

Ornithologie von Nordwest-Kansu nach den Forschungen von Walter Beick ( + ) in 

den Jahren 1926-1933. J. Ornith. 85. 
Thaler, E. 1979. Das Aktionssystem von Winter- und Sommergoldhahnchen (Regulus 

regulus, R. ignicapillus) und deren ethologische Differenzierungen. Bonn. Zool. 

Monogr. 12: 1-151. 

— 1988. Etho-okologische Differenzierungen bei amerikanischen Goldhahnchen: Regulus 

satrapa, Regulus calendula. Proc. Int. 100. DO-G Meeting, Current Topics Avian Biol. 

— 1990. Die Goldhahnchen. Neue Brehm-Bucherei 597. Wittenberg-Lutherstadt. 
Thaler-Kottek, E. 1986. The genus Regulus as an example of different survival strategies: 

adaptation to habitat and etho-ecological differentiation. Acta XIX Congr. Int. Orn. 

Ottawa: 2007-2020. 
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Nat. Hist. 100. New York. 

— 1959. The Birds of the Palearctic Fauna. Passeriformes. Witherby: London. 

Voous, K. H. 1977. List of Recent Holarctic Bird Species. British Ornithologists' Union, 

Whitman, C. O. 1898. Animal Behavior. Biol. Lect. Mar. Biol. Lab. Wood's Hole 285. 
Wolters, H. E. 1975-1982. Die Vogelarten der Erde. Berlin. 

— 1983. Die Vbgel Europas im System der Vogel. Baden-Baden. 

Addresses: Dr Hans Lohrl, Bei den Eichen 5, D-W-7271 Egenhausen, Germany; Prof. 
Ellen Thaler, Alpenzoo, Weiherburggasse 37, A 6020 Innsbruck, Austria. 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 209 M. Louette 

Barriers, contact zones and subspeciation in 
central equatorial Africa 

by Michel Louette 

Received 31 January 1992 

African forest and savanna avifaunas are recognised as being different, at 
least since Chapin's (1923) authoritative paper. Ecological vicariants do 
exist, but the number of biological species, composed of separate taxa, 
making contact in the forest/savanna border areas is restricted, contra 
Endler (1982). In fact, only few examples have been documented: e.g. 
Scopus umbretta (Bates 1931 , Louette 1981), Apaloderma narina (Clancey 
1959) and Campethera caillautii (Prigogine 1987). Similarly, the contact 
montane/lowland forest coincides very rarely with subspecies contacts: 
Dendropicos elliotti is one of the few examples (Louette 1981). There are, 
however, some superspecies contacts in both cases (see Prigogine 1980), 
but far less than Endler seems to admit. 

In the present paper, we are concerned with examples to show differing 
contacts within the central lowland forest itself, the region from southern 
Cameroon to eastern Zaire (Fig. 1). 

The ranges of forest birds and savanna birds penetrating forest in 
equatorial Africa were mapped in the Atlases by Hall & Moreau (1970) 
and Snow (1978). Some additions were made by Snow & Louette (1981) 
and Louette (1984, 1987, 1988, 1988a, 1989). These and other papers 
cited should be used to illustrate the ranges of several birds given as 
examples below; but an incomplete positioning of contact zones between 
subspecies in Africa was given by Meise (1975) and by Mayr & O'Hara 
(1986) and a general examination of the ranges in order to identify 
possible barriers is long overdue. 

Barriers and contact zones 

Some African birds are able to leave their habitat temporarily (many 
Holarctic migratory forest birds, of course, do so): e.g. the long-distance 
migratory savanna nightjars Caprimulgus rufigena and Macrodipteryx 
vexillarius cross the forest twice after the breeding season, breeding only 
in the south. But there are almost no migratory African lowland forest 

I listed elsewhere (Louette 1990) the 216 stenotopic forest species. The 
selection was arbitrary. Here I want to mention that for some at least, the 
wrong decision seems to have been taken: Telacanthura melanopygia, 
Neafrapus cassini, Eremomela turneri, Muscicapa tessmanni and Nectarinia 
cyanolaema are indeed also forest birds, according to my own definition. 
Moreau (1966), Forbes-Watson (1970) and Amadon (1973) came to com- 
parable figures. In any case, the degree of stenotopy varies within the 
group. I counted 156 stenotopic species covering virtually the whole 
forest block, leaving only a minority with restricted range therein. These 
contemporary ranges (and those of some other, eurytopic species) are 

M. Louette 



Figure 1 . Central equatorial Africa. The Lower Guinea rainforest block is indicated with 
oblique barring. 

considered to be positions taken up after radiation from a refuge and 
probably still dynamic (Mayr & O'Hara 1986). Suspected present day, as 
well as past, barriers (except for the presence of a vicariant species) 
include: degrees of altitude; inimical vegetation surrounding a refuge; 
savanna; hostile habitat in general: rivers and marsh. Examination of the 
ranges of such siblings as Estrilda nonnula and E. atricapilla allows one 
to presume that several such factors can act simultaneously (vicariants, 
philopatry, altitude, non-forest habitat, . . .). 

Competition with other species cannot explain the peculiar distri- 
butions of the stenotopic forest birds (nor the eurytopic savanna birds 
mentioned below), because usually no congeneric species are involved. 
The polyspecific forest genera Bleda and Malimbus (the latter including 2 
superspecies) were examined on this account, but no proof of competitive 
exclusion was found (Louette 1991a). However, the possibility of recent 
range restrictions or differences in ecological potential between the differ- 
ent parts of the forest cannot be excluded (Louette 1990). The restricted 
ranges are situated in particular areas outlined below, for which Louette 
(1990) produced a list of species {pace that given by Mayr & O'Hara 1986, 
which contains numerous errors, including the ranges for Glaucidium 
sjoestedti, Spermophaga poliogenys, Merops breweri, Nectarinia adelberti 
and others). These restricted ranges cover: 

1) the whole of Upper Guinea or Lower Guinea, supporting the 
strong impact on distribution of the Dahomey gap in western Africa, a 
present day savanna wedge in the forest (Bates 1931, Moreau 1966); 

2) particular parts of Lower Guinea in Cameroon/Gabon, in the 
Zaire basin proper (only a few), and in a small eastern area; 

Bull. B.O.C. 1 1 2A 211 Subspeciation : central equatorial Africa 

3) the coastal forest for 3 species: Tauraco macrorhynchus, 
Gymnobucco calvus and Nectariniafuliginosa. 

There being no obvious ecological reason for this pattern and assuming 
those species under 2) and 3) did in fact have time and opportunity to 
spread out in the adjoining apparently suitable habitat, but did not do so, 
there must be a historical reason. The study of philopatry, with its genetic 
causes, is still in its infancy (Greenwood 1987). Land areas with high 
diversity and endemism correspond to refuges and centres of evolution 
during dry climatic phases according to several authors quoted by Prance 
(1982) and Crowe & Crowe (1982). Crowe & Crowe lacked information 
on the non-existence of an earlier suspected range gap for several bird 
species (such as Apaloderma aequatoriale) in central Zaire (Louette 1984). 
Mayr & O'Hara (1986) and Prigogine (1988) again discussed the refuges 
for birds specifically in this region and Prigogine accepted a Zaire Basin 
refuge which was not admitted by previous authors. Colyn et al. (1991), 
basing themselves on Primate ranges in the same region, similarly do 
not find a (geographic) diversity gradient, accepting also a quaternary 
(central) fluvial refuge, south of the present middle Zaire. We lack, 
however, information on possible barriers in the period since the last dry 

Range limitation for forest birds by rivers 

In South America, Capparella (1991) finds a whole series of bird 
species limited in range by large rivers (hundreds of cases?), or with 
separate subspecies or proven genetic differentiates on each bank. In 
central Africa, a similar phenomenon caused by several rivers was shown 
by Colyn (1987, 1 988) for Primates. So it is reasonable to enquire whether 
this factor applies in African birds. 

Very few subspecies ranges are given as delimited by rivers by White 
(1960, 1961, 1962, 1963, 1965), but that this could be the case for, for 
example, Glaucidium tephronotum, Tockus hartlaubi and Alethe diademata 
could be inferred. The maps in the Atlases for, for example, Gymnobucco 
pelijsladeni, Trichastoma albipectusj cleaveri , Apalis rufogularis races and 
Anthreptes fraseri races, also do give this impression for the Zaire river, 
but the limitation is probably due to coincidence, in the same way as the 
range of Ceratogymna elata or the contact zone of Malimbus cassinij 
scutatus is limited by the Sanaga river (Louette 1981). In the Tauraco 
persa superspecies, where the Ubangi/Zaire was a suspected barrier 
(Snow 1978), persa crosses it in fact towards the east in 2 places (Snow & 
Louette 1981). 

There seems to be a genuine case in the genus Centropus: C. neumanni 
lives north and C. anselli south of the Zaire river in Zaire, but C. anselli 
also on the right bank towards Cameroon. In addition, C. neumanni does 
not reach the southern Kivu — it is definitely a philopatric species. (The 
other contact in the superspecies, C. anselli / leucogaster y in Cameroon and 
without introgression, is not along a river — Louette 1981). In investigat- 
ing whether a coucal population would be limited by a very broad river, 
at least several hundred metres wide in the stretch of river considered 
and with a quite stable regime (Devroey 1951) and containing forested 

M. Louette 212 Bull. B.O.C. 1 12A 

islands, I found traces of introgression in the 'contact area', west of 
Kisangani, showing that the Zaire river barrier is actually not absolute 
(Louette 1986). 

Barriers by rivers seem to occur in African birds otherwise only in a few 

1 )Francolinus squamatus and F. ahantensis are separated by the lower 
Niger (Elgood 1982). 

2) Gutter a plumif era is apparently squeezed by the Sanaga (Dejaifve 
1991 mentions an unconfirmed sighting on the right bank) and the Zaire 

3) Agelastes niger lives from the Nigerian/Cameroon border in the 
west (Dejaifve 1991; limited by the Cross river?) to the right bank of the 
Zaire (without penetrating towards southern Kivu). 

4)Afropavo congensis has, in the opinion of all previous workers, a 
most puzzling range, present as it is on both banks of the Zaire, but living 
in eastern Zaire only. Verheyen (1962), suggested it is limited by the very 
humid soils in the western part of the Zairean (marsh) forest on the left 
bank, and by high altitude in the east. This may well be so; it is hard to 
believe that it would be excluded by the much smaller and even partly 
sympatric Agelastes niger, as suggested as plausible by Snow (1978). But 
why is it absent from the middle part of the right bank where the forest is 
'dry', as in the bird's actual range (IUCN 1990)? Possibly these 2 species 
became trapped in pockets of forest on the 2 different banks of the Zaire or 
Aruwimi rivers during a dry period, before spreading out and living now 
mostly, but not exclusively, on different banks. 

The absence of both Centropus neumanni and C. anselli, and also 
Agelastes niger from the well forested southernmost Kivu suggests that 
this region was barriered from their refuge, configuration of the rivers 
perhaps prohibiting colonisation in this area by these 'philopatric' species 
avoiding large river crossings. To the contrary, Afropavo congensis was 
possibly on the right bank of the Zaire, but later crossed it upriver from 
say Kisangani, penetrating to and beyond the left bank; it has crossed the 
Aruwimi as well (see map in Verheyen 1962). 

It is noteworthy that other forest galliformes, in the genera Guttera and 
Francolinus, are not delimited by the entire Zaire river. F. lathami shows a 
peculiar pattern of distribution, with the population in south-central 
Zaire morphologically so similar to the one towards Cameroon/ Gabon 
that it is considered consubspecific and different from the population 
more to the north in Zaire, on the right bank of the Zaire river (Louette 
1984). This southern population must have arrived from the west (or vice 
versa), crossing the Zaire river in its lower reaches, rather than arriving 
from the more plausible northern population; but the latter possibility 
may indeed have been excluded by the middle Zaire river (or Ubangi 
river) being a barrier at the appropriate period. There are other examples 
of extension of races of strong flying lowland forest birds from western 
origin towards southern Zaire or northern Angola or both, suggesting 
possibly simply another forest localisation formerly. 

In contrast to Amazonia, it is clear that equatorial Africa does not have 
a river system separating bird populations to a great extent. A study of 

Bull. B.O.C. 1 1 2A 213 Subspeciation : central equatorial Africa 

the genetic differentiation of all these species on both banks would be 

Particular savanna species delimited by forest 

One wonders what would be the barrier in the species where the range 
includes a particular part of the forest, though the largest part of the range 
is in savanna; an example of this distribution of eurytopic species is Buteo 
auguralis (Louette 1991). It migrates to rather high latitudes in the north- 
ern hemisphere in Africa. However, it is present (only as a migrant?) in 
the whole forested region of Upper Guinea and from western Cameroon 
towards northwestern Angola; it is absent towards the east in central and 
southern Zaire in forest as well as in the periforest/savanna, although 
there is no vicariant. Other species with a rather similar distribution 
are not rare: Agapornis pullaria, Colius striatus, Centropus monachus, 
Smithornis capensis, Chloropeta natalensis, Zosterops senegalensis and 
Poeoptera lugubris. The fact that these eurytopic savanna birds occur in 
'the Cameroon/Gabon forest refuge' and not in 'the Zaire Basin refuge', 
augments diversity there and explains in part Crowe & Crowe's (1982) 
findings. However, in my opinion these species do not really belong to the 
forest avifauna. Further, their absence in accessible savanna points to a 
historical reason (and philopatry) for the peculiar distribution. But there 
may be an ecological one — maybe they do not penetrate into marshforest 
or into the deepest part of the forest block. 

Haffer (1 988) estimates c. 1 00 land bird species in Amazonia are limited 
to riverine surroundings in forest. Such a group exists also in forested 
central Africa, but its composition in species is much smaller: Pseudo- 
chelidon eurystomina (migratory), Riparia congica, Nectarinia congensis 
and Quelea anomala. These live only alongside the Zaire and its major 
tributaries, apparently enclosed by 'hostile habitat (forest)' and unable to 
escape to possibly more favourable habitat elsewhere; Prigogine (1988) 
incorporates them in his group originating in the Zaire Basin refuge, 
together with real forest birds with restricted range. There is a possible 
second type in the forest: Bradypterus grandis lives in riverine marshes 
along the Dja river (it occurs also in Gabon). Possibly an almost unknown 
species such as Ploceus batesi will reveal itself as also being confined to 
riverine forest habitat. Other typical riverine birds such as Ploceus mela- 
nocephalus duboisi, P. pelzelni and Merops malimbicus are not completely 
enclosed by the forest block, although they are restricted in range to 
central Africa. In addition there are other riverine species in central 
Africa, but surrounded by savanna (outside the scope of this paper), 
suggesting that the forest is a barrier by chance for the riverine group. 
Similarly, Anthreptes gabonicus and Ploceus subpersonatus are limited to 
mangroves, the last one to a very restricted part of them. 

That forest can be a solid barrier is proven indirectly by the stenotopic 
savanna bird penetration from the northern woodland and savanna 
through a (former) corridor along the Ubangi river towards Lower 
Zaire, such as Dendropicos goertae (Louette & Prigogine 1982). Other 
similar cases are Numida meleagris, Caprimulgus climacurus, Crinifer 
piscator, Phoeniculus aterrimus and Batis minor (Louette 1987). No differ- 
entiation, or only minor, has occurred suggesting recent immigration. 

M. Louette 214 Bull. B.O.C. 1 12A 

The surroundings of the lower Ubangi were even contemporarily not 
covered with forest, large 'esobe' grasslands existing in this general area. 
These species definitely must have followed a western (central) route, 
because east of the forest belt the savanna connection is blocked by a 
vicariant. There are no examples of a penetration northwards (but poss- 
ibly they would spread out rapidly and cannot be detected by examination 
of range maps). The last arid period seems to have culminated at 18,000 
years BP (van Zinderen Bakker 1986), with semi-arid conditions in the 
'central Congo' region. The aridity was of a magnitude much larger than 
needed to explain these penetrations, permitting a whole savanna fauna 
exchange. Probably Francolinus coqui (towards the north) and F. albo- 
gularis (towards the south) achieved the penetration during such a period. 
The present positioning of the savanna species in Lower Zaire must have 
taken place much later (the equatorial forest reappeared from 9000 years 
BP — Maley 1989), with a corridor of grassland as a sufficient gateway. 
Also, the separation of the forest bird populations referred to above as 
being possibly due to the Zaire river may simply have been produced by 
this vegetation corridor along the river, not by the river itself. 


Subspeciation within the Lower Guinea forest block proper is given in 
White's check-lists. He does not differentiate races based on colour or on 
measurements, nor abrupt and clinal ones. Since White's papers were 
written, no complete review of subspeciation in Africa has been made. 
Therefore we still use White's races provisorily to render geographical 
variation, although, no doubt, in many cases too few statistically valuable 
criteria were used to create them (see Barrowclough 1982). 

Contacts between subspecies of forest birds, as for borders of species' 
ranges, are numerous in the general region of Mount Cameroon, clearly a 
suture line of an old non-forest gap (Louette 1981; but see Maley 1989, 
who postulates montane forest descending to lower levels here during 
part of the Quaternary). Some of the contacts are somewhat to the west, 
others to the east of Mount Cameroon (cf. Meise 1975), quite possibly a 
result of different colonisation speed rather than an indication of separate 
gaps(cf. Mayr&O'Hara 1986); also, the supposed influence of the Sanaga 
river may in fact be a consequence of this Mount Cameroon gap. 
Examples rather far to the east from the Mount Cameroon suture line 
include: Lybius hirsutus, Pitta angolensis and Stiphrornis erythrothorax. 
With the contact still more to the east is Terpsiphone rufocinerea, studied 
by Chapin (1953); equally Alcedo leucogaster, Bycanistes fistulator, 
Psdalidoprocne nitens and Alethe poliocephala qualify. Some western races 
are present in northwestern Angola, but for Spermophaga haematina the 
eastern race is there and I suggested a "push" from the western popu- 
lation in the southern Zaire sector towards the east (Louette 1988). 
Subspecies bordering the Zaire river were mentioned above. A former 
gap (savanna, esobe grassland, lake, river?) in west-central Zaire may 
explain these positions. 

Clines in colour or dimensions or both are present in many forest birds, 
with the gradient changing from west to east somewhere in Zaire (Louette 

Bull. B.O.C. 1 1 2A 215 Subspeciation : central equatorial Africa 

1991a gave several examples: e.g. Andropadus latirostris, Bleda syndactyla 
and B. eximia). (Others are morphologically homogenous throughout this 
part of the range, though differing elsewhere; for example Andropadus 

The morphological differences in bird species in Lower Guinea Gust as 
are those for Upper Guinea, listed by Bates 1931) do not contradict the 
refuge hypotheses. The contacts between (incipient) subspecies in Lower 
Guinea may be the result of both an east and a west colonisation from the 
Cameroon-Gabon and Albertine Rift refuges (which other species due to 
philopatry are still occupying solely — Crowe & Crowe 1982, Prigogine 
1988). Possibly, however, some of the differentiation is due to adaptation 
to local conditions: the study of this phenomenon is far from finished 
(Boag & Van Noordwijk 1987). 


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America: a comparative review. Smithsonian Institution Press, Washington. 
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Buckley (eds). Avian Genetics. Academic Press, London. 
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Chapin, J. P. 1923. Ecological aspects of bird distribution in tropical Africa. Am. Nat. 57: 


— 1953. The Birds of the Belgian Congo. Bull. Am. Mus. Nat. Hist. 75A: 1-821. 
Clancey, P. A. 1959. Miscellaneous taxonomic notes on African birds. XII. Durban Mus. 

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Biogeogr. 18:403-407. 
Crowe, T. M. & Crowe, A. A. 1982. Patterns of distribution, diversity and endemism in 

Afrotropical birds. J. Zool. (London) 198: 417-442. 
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Mimeo report for Wildlife Conservation International, New York. 70 pp. 
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western extremities (Kakamega, Kenya and Mt. Nimba, Liberia). Abstract XV Congr. 

Int. Orn. 
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129: 1-53. 
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Museum (Natural History). 

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IUCN. 1990. La Conservation des Ecosystemes Forestiers du Zaire. (Base sur le travail de 

Charles Doumenge). IUCN, Gland. 
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Koninklijke Academie voor Wetenschappen, Letteren en Schone Kunsten van Belgi'e. 

Klasseder Wetenschappen, 43 (Nr. 163): 1-295. 

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— 1986. Geographical contacts between the taxa of Centropus in Zaire, with the description 

of anew race. Bull. Brit. Orn. CI. 106: 126-133. 

— 1987, 1988, 1988a, 1989. Additions and corrections to the avifauna of Zaire (\).Bull. Brit. 

Orn. CI. 107: 137-143; (2). 108: 43-50; (3): 108: 112-120; (4): 109: 217-225. 

— 1990. Distribution patterns in African lowland forest birds. In: G. Peters & R. Hutterer 

(eds). Proceedings of the International Symposium on Vertebrate Biogeography and 
Systematics in the Tropics. Museum A. Koenig, Bonn, Germany. 

— 1991. The red-tailed buzzards of Zaire. Bull. Brit. Orn. CI. Ill: 51-55. 

— 1991a. Geographical morphometric variation in birds of the lowland equatorial forest of 

Africa. Acta XX Congressus Internationalis Ornithologici: 475-482. 
Louette, M. & Prigogine, A. 1982. An appreciation of the distribution of Dendropicos goertae 

and the description of a new race (Aves: Picidae). Rev. Zool. Afr. 96: 461-492. 
Maley, J. 1989. Late Quaternary climatic changes in the African rain forest: forest refugia 

and the major role of sea surface temperature variations. In: M. Leinen & M. Sarnthein 

(eds). Paleoclimatology and Paleometeorology : Modern and past patterns of global 

atmospheric transport. NATO ASI series. Kluwer. 
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forest refuge hypothesis. Evolution 40: 55-67. 
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Abn. Verh. Naturwiss. Ver. Hamburg 18/19: 187-254. 
Moreau, R. E. 1966. The Bird Faunas of Africa and its Islands. Academic Press. 
Prance, G. T. (ed). 1982. Biological Diversification in the Tropics. Columbia University 

Prigogine, A. 1980. Etude de quelques contacts secondaires au Zaire oriental. Gerfaut 70: 


— 1987. Hybridization between the megasubspecies caillautii and permista of the 

Green-backed Woodpecker Campethera caillautii. Gerfaut 77: 187-204. 

— 1988. Speciation patterns of birds in the Central African forest refugia and their 

relationship with other refugia. Acta XIX Congr. Int. Orn.: 2537-2546. 
Snow, D. W. (ed). 1978. An Atlas of Speciation in African Non-passerine Birds. British 

Museum (Natural History) 
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Addenda and Corrigenda 2. Bull. Brit. Orn. CI. 101: 336-339. 
van Zinderen Bakker, E. M. 1986. African climates and palaeoenvironments since 

Messinian times. S. Afr. J. Sc. 82: 70-71. 
Verheyen, W. N. 1962. Quelques donnees concernant le dimorphisme sexuel, la distri- 
bution geographique d'Afropavo congensis Chapin ainsi qu'un essai de bibliographic 

generale. Bull. Soc. Roy. Zool. Anvers 26: 7-15. 
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Parts I, II, III. Occ. Pap. Natn. Mus. S. Rhod. 24B: 399-430; 26B: 653-738. 

— 1 96 1 . A Revised Check List of African broadbills, pittas, larks, swallows, wagtails and pipits. 

1 962. A Revised Check List of African shrikes, orioles, drongos, starlings, crows, waxwings, 
cuckoo-shrikes, bulbuls, accentors, thrushes and babblers. 1963. A Revised Check List of 
African flycatchers , tits, treecreepers, sunbirds, white-eyes, honey eaters, buntings , finches , 
weavers and waxbills. 1965. A Revised Check List of African non-passerine birds. 
Government Printer, Lusaka. 

Address: Dr. Michel Louette, Koninklijk Museum voor Midden- Afrika, B-3080 Tervuren, 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1 992, 1 1 2A 21 7 G.J. Morel & C. Chappuis 

Past and future taxonomic research in 
West Africa 

by Gerard J. Morel &.■ Claude Chappuis 

Received 27 April 1992 

In the opinion of Brown et al. (1982) only some 20 new species of birds 
have been discovered these last 20 years in the whole African continent, 
i.e. one species annually on average. Since discovery of new species is 
most likely in montane forests, where endemism is enhanced, and in 
regions where exploration is difficult, West Africa would appear at a 
special disadvantage in this respect. We shall review the forms (species or 
subspecies) new to science discovered in West Africa over the last 30 
years, with emphasis on the new techniques — particularly bioacoustics — 
that give taxonomy a new impetus. For the Non-passerines, we have 
adopted the sequence of The Birds of Africa; for the Passerines, we have 
followed Bannerman (1953); for the new forms we use the names pro- 
posed by the authors; for Stizorhina, we have adopted the names given by 
Howard & Moore (1980). 

The discovery of new forms can be attributed to 2 main techniques. 

New forms from the study of skins 

The study of skins, either obtained during recent exploration or of older 
origin, the classic technique, aided by morphological analysis, is still 
widely used. 

PURPLE HERON Ardea purpurea bournei (Naurois 1 966) 

Compared with the nominate, bournei is very pale; the paleness of the 
first specimen that reached the British Museum was merely ascribed to 
bleaching (Bannerman & Bannerman 1968). Restricted to Sao Tiago 
island in the Cape Verde archipelago, its total population may be under 
200 pairs. It builds its nest in trees and forages on dry, even stony ground. 
Not recognized by Brown et al. (1982). 

GREY HERON Ardea cinerea monicae (Jouanin & Roux 1963) 

Also a very pale form, with a population of 1000—2000 pairs, restricted 
to the Banc d'Arguin islands, Mauritania. Owing to its unique nesting 
behaviour (a scrape on the ground), to its entire life being spent in 
marine waters and its distinct plumage, it could be considered a full 
species (Mahe 1985). Considered a doubtful form by Brown et al. 

SPOONBILL Platalea leucorodia balsaci (Naurois & Roux 1 974) 

Distinguished by its black bill without a yellow tip and by a near 
absence of yellow buff on the chest. Also restricted to Banc d'Arguin, with 
a population of several thousand pairs (Mahe 1985). The bulky nest is 
piled upon low clumps of Chenopodiaceae. 

G.J. Morel & C. Chappuis 218 Bull. B.O.C. 1 12A 

COE'S HONEYGUIDE Melignomon eisentrauti (Colston 1981-especially 
footnote p. 290; Louette 1981) 

This new species is only the second within the Melignomon genus. 
Originally discovered by Serle (1 959: 65) as early as 1 956, then redescribed 
by Eisentraut in 1963, it was thought by both that their specimens were 
mere immatures of M. zenkeri. First described by Serle (1959) from 
Mount Nimba, Liberia, this honeyguide is certainly widespread in Upper 
Guinea forests. (Details of nomenclature and description by the 2 separ- 
ate authors (Colston 1981, Louette 1981) are also given in Colston & 
Curry-Lindahl 1986.) (See Vuilleumier et al. this volume.) 

[No English name given by author] Phyllastrephus leucolepis (Gatter 1 985) 

The type of this new species is represented by one specimen of un- 
determined sex, collected in Liberia, 6°12'N,8°irW, in a "transitional 
zone between evergreen and semideciduous tropical rainforest". Several 
individuals were observed, usually in bird parties including bulbuls, sun- 
birds and malimbes. The olive brown wing shows 2 pale bars, which are 
diagnostic, as this bulbul forages through the twigs with half opened 
wings. It seems that the wing pattern is used as an optical signal. (See 
Vuilleumier et al. this volume.) 

GREY-HEADED BRISTLE-BILL Bleda canicapilla moreli (Erard 1991) 

Based on specimens collected in Lower Casamance, Senegal, differs by 
its paleness and its bill shape from the nominate form which is only found 
in forest, from Guinea to Nigeria. 

AFRICAN REED WARBLER Acrocephalus baeticatus guiersi (Colston & 
Morel 1984) 

A. baeticatus remained unrecorded west of Chad until as late as 1960, 
when it was found in Senegal (Morel & Roux 1962). Subsequently it was 
described as a new subspecies (Colston & Morel 1984). Its range remains 
unknown; since guiersi lives in reedbeds, a naturally discontinuous 
habitat, it could be isolated. Widespread also in Mali (Lamarche 1 980-81 ) 
and localized in Niger (Giraudoux et al. 1988). 

RUFOUS CANE- WARBLER Acrocephalus rufescens senegalensis (Colston & 
Morel 1985) 

Based on skins, obtained in Senegal, where it seems to live mainly if not 
exclusively in reedbeds; in Cameroun it is also found in sugar-cane. In 
Senegal, the pairs were widely spaced. As a whole, A. rufescens } a secretive 
but vocal species, is poorly known in West Africa. 

PECTORAL PATCH CISTICOLA Cisticola brunnescens mbangensis (Chappuis 
& Erard 1973) 

Restricted to the montane region of Adamawa, Cameroun, where it 
inhabits meadows with very short grass on stony ground. It is of smaller 
size, lighter coloration, with upperparts less intensely streaked, than the 
nominate race, but the voice seems similar. 

ANNA'S FOREST FLYCATACHER Melaenornis annamarulae 
(Forbes-Watson 1970) 

A species of the forest canopy, discovered on Mount Nimba, Liberia, 
and also found in southwestern Ivory Coast. 

Bull. B.O.C. 1 12A 219 Taxonomic research in W. Africa 

IBADAN MALIMBE Malimbus ibadanensis (Elgood 1958) 

Hitherto regarded as endemic in southern Nigeria, there is one record 
recognized now from Owerri, east of the lower Niger (Marchant in 
Bannerman 1949) but first identified as M. cassini. Similarly Bannerman 
mentions cassini from Ibadan, recorded by Marshall. With the recog- 
nition of ibadanensis as a distinct species (Elgood 1958), both Marchant 
and Marshall agreed their sightings were almost certainly of ibadanensis, 
and Field (1979) accepted ibadanensis as occurring at Owerri. Now it 
seems likely that recent records of cassini from Tafo, Ghana ( SS only) 
(Grimes 1987) are likely to have been sightings of ibadanensis (Elgood in 
press). Formerly not uncommon, but local, at forest edges, in secondary 
forest and even gardens; but in view of a 10 year gap without any records 
(Elgood 1988), the species has come to be regarded as "endangered" 
(Collar & Stuart 1985). 

New forms from acoustical signals 

This group comprises new subspecies or species discovered by means of 
acoustical analysis, i.e. with the assumption that voice — or significant 
elements of a bird's vocalizations — are specifically distinct. This tech- 
nique is valuable: (1) when 2 forms are morphologicaly very similar (e.g. 
Streptopelia roseogriseajS. decaocto); (2) when of 2 closely related forms, 
one breeds in the Palaearctic and the other in the Afrotropics (e.g. Cuculus 
canorusjC. gularis); (3) when a polymorphic species is widely distributed 
over the continent (e.g. Eupodotis ruficrista). The acoustical analysis is 
usually confirmed by a morphological study. 

CRESTED BUSTARD Eupodotis ruficrista savilei (Chappuis et al. 1979) 

The race savilei, only found in West Africa, is vocally so distinct from 
the 2 other races gindiana and ruficrista by reason of the frequency used 
and by the rhythm and structure of the phrasing that an observer familiar 
with the latter 2 races may wonder what bird he is listening to (Fig. 1). E. 
r. savilei shows differences also in colour pattern and in nuptial display. 
Chappuis et al. (1979) recommended restoring savilei to its previous 
specific status. 

AFRICAN COLLARED DOVE Streptopelia roseogrisea (Chappuis 

Long considered a mere subspecies of the Eurasian Collard Dove S. 
decaocto (Heim de Balsac & Mayaud 1962, Mackworth-Praed & Grant 
1970) because of similar plumage and size; but comparison of their songs 
and flight calls (Fig. 2) compels recognition of 2 distinct species 
(Chappuis 1974-1985), confirmed by Urban et al. (1986). 

EUROPEAN CUCKOO Cuculus canorus and AFRICAN CUCKOO Cuculus 

Because of their nearly identical adult plumage and closely comparable 
songs, these 2 forms have been considered as conspecific by several 
authors (e.g. White 1965, Voous 1960). This opinion was, however, 
revised as a result of morphological differences found in the young (Payne 
1977). Confirmation is found in acoustical differences, even though these 

G.J. Morel & C. Chappuis 220 Bull. B.O.C. 1 12A 

are slight and in a species with strictly inherited song: in canorus the 2 
(sometimes 3) notes are always on a descending scale, but mgularis always 
ascending or monotonous. 


Considered conspecific by Snow (1978) and also by Fry et at. (1988), 
the 2 are indeed morphologically close, but their voices are very distinc- 
tive (Chappuis 1 974—85). In the last historical contact zone between these 
2 forms before the last glaciation (i.e. in the north/south Sahara), there is 
an absence of frequency overlap in the song of these 2 forms, with a gap of 
250 hz and also an absence of clinal variation of frequency, which is 
1300 hz in southern Morocco (recent personal measurements) compared 
with 1000 hz in West Africa. These differences, more distinct and rigid 
within the last contact zone than away from it (Van der Weyden 1973), 
suggest an ancient separation, prior to the geographical isolation, by 
means of vocal separation of these 2 forms, which thus deserve specific 

AFRICAN BARRED OWLET Glaucidium capense etchecopari (Erard & Roux 

Smaller than the nominate race and more restricted to forest, etchecopari 
ranges from the forests of Mount Nimba, Liberia (its place of discovery) 
through the southern forest belt of Ivory Coast and is common in the 
Ndouci-Lamto area. Insufficient acoustical data originally led to the con- 
clusion that the east and west African populations were specifically dis- 
tinct; but further studies have shown that both forms have similar vocal 
signals and are therefore only subspecies (Chappuis 1974—85). 

BROAD-BILLED ANT-THRUSH Stizorhinafinschi 

These 2 rather similar forms present acoustical differences in both their 
songs and in their cries: lower pitch (frequency ratio of 1.8) and longer 
duration (ratio of 1.55) for finschi (Fig. 3). These differences, taken separ- 
ately, exceed what is normally expected in 2 populations of one species 
occupying the Guinean and Congolese forest blocks; while taken 
together, they support the diagnosis of 2 populations whose acoustical 
isolation has been achieved and which should be treated as a 

PLAINTIVE CISTICOLA Cisticola dorsti (Chappuis & Erard 1991) 

Formerly assigned to C. ruftceps as the subspecies C. r. mongalla. 
Compared with C. ruficeps, the newly named C. dorsti exhibits a number 
of subtle colour differences, a longer tail and smaller white tail spots. 
Acoustically ruficeps and dorsti have nothing in common (see sonagrams 
in Chappuis & Erard 1991). C. dorsti inhabits the grass steppe with low 
bushes of northwestern Nigeria, northern Cameroun and southern Chad. 
It lives in sympatry with C. ruficeps guinea. 

RIVER PRINIA Prinia fluviatilis (Chappuis et al. in press) 

First found on the Upper Niger in 1969, now also in Chad and more 
recently in northwestern Senegal, its range remains to be elucidated. The 

Bull. B.O.C. 1 12A 221 Taxonomic research in W. Africa 

song of the River Prinia was (and certainly remains) confused with that of 
the Tawny-flanked Prinia P. subflava. Influviatilis there is only a slow and 
moderate variation in frequency, whereas in subflava it varies sharply and 
extensively — the notes of fluviatilis never show on a sonagram the fine 
striations (due to frequency modulation) produced by subflava (Fig. 4). 
These vocal characteristics are recognisable in the field and in addition 
the habitats of the 2 prinias are specifically distinct. Subtle but definite 
morphological differences have also been revealed. 

and SHARPE'S APALIS A. sharpii (Chappuis 1974-85, Chappuis 1980) 

Acoustical analysis was used to separate a member of this group, the 
Chestnut-throated Apalis A. porphyrolaema, from others (Keith & Gunn 
1971). The above 4 Apalis , which were given specific status by Bannerman 
(1953) and by Mackworth-Praed & Grant (1970), were treated by White 
(1960) as A. rufogularis, A. sh. sharpii, A. sharpii bamendae and A. sharpii 
goslingi. White's arrangement is not supported by these forms' vocal 
structure: rufogularis and sh. sharpii utilize a repertoire of structurally 
similar motifs (with positive reactions to each other's playback in the 
field) and must be treated as a superspecies. goslingi and bamendae utilize 
a repertoire of simple notes, of strongly modulated frequency in bamendae, 
but little modulated and of a more rapid tempo in goslingi (Fig. 6). The 
latter are 2 distinct species that live in very different habitats. 

JAMBANDU INDIGOBIRD Vidua raricola (Payne 1982) 

Male raricola mimic the song of the Black-bellied Fire-finch 
Lagonosticta rara and the young indigobirds mimic the latter's mouth 
pattern (gape tubercles and spots on the roof of the mouth). The distri- 
bution of V. raricola matches closely that of L. rara (see later discussion). 
They are both found in Sierra Leone, Ghana and northern Cameroun. 
(See Vuilleumier et al. this volume.) 

BAKA INDIGOBIRD Vidua larvaticola (Payne 1982) 

Parasitizes and mimics vocally the Black-faced Fire-finch Lagonosticta 
larvata. V. larvaticola is distinguished by the same adaptations to its host 
as those of V. raricola (see later discussion). It ranges from Senegambia to 
Ethiopia. (See Vuilleumier et al. this volume.) 


The above examples are given in a plea to restore the importance of avian 
taxonomic research, at present so severely neglected in several countries, 
emphasised by the drastic reduction in funds apportioned to museums. 
Denial of research amounts to a threat to the collections which are the 
foundations of these museums. This disfavour has several causes. 
Taxonomic research has become overshadowed by the great impulse of 
more recent disciplines, such as ecology and ethology; in comparison 
taxonomy is wrongly coming to be considered an outdated discipline. 
In addition, a frequently uncritical regard for life demands preclusion of 
the killing of any bird whatever for whatever reasons, enhanced by 

G. J. Morel & C. Chappuis 222 Bull. B.O.C. 1 12A 

unconfirmed opinion that museums are well stocked with specimens and 
that collecting is a direct unmeasured threat to uncommon species. 
Nevertheless, knowledge and documentation of many species is markedly 
insufficient for their own conservation, particularly in West Africa, 
whereas the insatiable thirst of some past collectors no longer exists. 
Many species are considererd endangered on account of their small 
populations, while knowledge of their taxonomic status as well as of their 
degree of genetic isolation is possibly essential for their protection and 
even their survival. 

The new species cited are examples of many others that have required 
or require taxonomy to resolve their problems. The Spoonbill Platalea 
leucorodia and the Little Bittern Ixobrychus minutus breed in the Senegal 
valley, i.e. within the tropics. The Spoonbill has not been collected, so its 
taxonomic status or whether it is endemic and requires especial protec- 
tion is unknown; the Little Bittern is thought to be of the nominate race, 
but this needs confirmation (Morel & Morel 1989). The Glossy Ibis 
Plegadis falcinellus that was nesting in northern Mali (Morel & Morel 
1966) was not observed again and its taxonomic status also remains 
unknown. In the contact zone of the western (savilei) and of the eastern 
(gindiana) African Crested Bustard Eupodotis ruficrista the question 
whether the 2 populations are vocally isolated deserves study. The chance 
discovery of other new species undoubtedly awaits the knowledgeable 
explorer, but this will happen more and more rarely. 

Taxonomy, however, is receiving fresh impulse from modern tech- 
niques with live birds. Mathematical aid (e.g. discriminant analysis) can 
be instrumental in morphological studies (wing, tail and tarsus length) of 
outwardly similar forms, e.g. Cisticola dorsti and subspecies of C. ruficeps 
(Chappuis & Erard 1991). Also, when only tiny fragments of feather or 
very small samples of blood are available, DNA analysis can help to 
distinguish allied forms, as was the case in describing Laniarius liberatus 
(Smith et al. 1991) in Somalia, where one live specimen only could be 
secured, and had to be released. (See also Vuilleumier et al. this volume.) 

About half of the new forms mentioned above from West Africa clearly 
indicate that bioacoustics (supported by biometrics) was the decisive 
technique used in their discovery (Prinia fluviatilis, Vidua spp.) or in 
elucidating their superspecies status (Otus scops, Cuculus canorus . . .). 
Bioacoustics is relevant in 2 types of problem. Firstly, with populations in 
sympatry: no two sympatric populations with distinct vocalizations can 
be from a single species, more especially if these vocalizations can be 
correlated with distinct habitats. Secondly, it is relevant with allopatric 
populations, when assessment is more delicate and is based on the import- 
ance of the acoustical deviation in the following main parameters: range of 
notes, their speed of frequency variation, and the harmonic and temporal 
structure of the call or song. These differences, of course, will be all the 
more significant if they concern several of these parameters simul- 
taneously (Chappuis 1980). The value of vocalizations as a means of 
distinguishing forms is now recognized, and the diagnosis of every new 
species should generally include a paragraph on 'Voice' with sonagrams. 

Finally, the outstanding study of Payne (1982) on the genus Vidua 
deserves mentioning. The confusing black plumage of all Vidua ( = 

Bull. B.O.C. 1 12A 223 Taxonomic research in W. Africa 

Hypochera) males, more or less greenish or bluish depending on the light, 
had always been a challenge to taxonomists. Amongst other parasitic 
avian species, the specific adaptation of the nestling's mouth marks to that 
of the host, as shown by Payne, is unique. The number of queried syno- 
nyms and the nomina dubia still left unresolved attests to the difficulty of 
the task and is also a stimulating invitation for further research, including 
especially the vocalisation differences and mimicry of the male Vidua. 


We express our thanks to J. H. Elgood over M. ibadanensis and to J. F. Monk for improving 
our text and our English. 


Bannerman, D. A. 1 949. The Birds of Tropical West Africa. Vol. 7. London, Crown Agents. 

— 1953. The Birds of West and Equatorial Africa 2 vols. Oliver & Boyd. 

Bannerman, D. A,. & Bannerman, W. M. 1968. History of the Birds of The Cape Verde 

Islands. Oliver & Boyd. 
Brown, L. E., Urban, E. K. & Newman, K. 1982. The Birds of Africa. Vol. 1. Academic 

Chappuis, C. 1974-1985. Illustration sonore de problemes bioacoustiques poses par les 

oiseaux de la zone ethiopienne. Alauda 42: 197-222 & 467-500, 46: 327-355, 47: 192- 

212; with accompanying discs. Soc. Etudes Orn. Museum, 4, avenue du Petit-Chateau. 

91800 Brunoy, France. 
— 1980. Study and analysis of certain vocalizations as an aid in classifying African 

Sylviidae. Proc. IVPan-Afr. Orn. Congr. 1976: 57-63. 
Chappuis, C. & Erard, C. 1973. A new race of Pectoral-patch Cisticola from Cameroun. 

Bull. Brit. Orn. CI. 93: 143-144. 
— , — 1991 . A new cisticola from west-central Africa. Bull. Brit. Orn. CI. 1 1 1 : 59-70. 
Chappuis, C, Erard, C. & Morel, G. J., 1979. Donnees comparatives sur la morphologie et 

les vocalisations des diverses formes d'Eupodotis ruficrista. Malimbus 1: 74-89. 
— , — , — (in press). Morphology, habitat, vocalizations and distribution of the River Prinia 

Prinia fluviatilis Chappuis. Proc. VII Pan-Afr. Cong. 
Collar, N. J. & Stuart, S. N. 1985. Threatened Birds of Tropical West Africa. 3rdEdn. Part 1. 

ICBP/IUCN Red Data Book. ICBP. 
Colston, P. R. 1981 . A newly described species of Melignomon (Indicatoridae) from Liberia, 

West Africa. Bull. Brit. Orn. CI. 101: 289-291. 
Colston, P. R. & Curry-Lindahl, K. 1986. The Birds of Mount Nimba, Liberia. British 

Museum (Natural History), London. 
Colston, P. R. & Morel, G. J. 1984. A new subspecies of the African Reed Warbler 

Acrocephalus baeticatus from Senegal. Bull. Brit. Orn. CI. 104: 3-5. 
— , — 1985. A new subspecies of the Rufous Swamp Warbler Acrocephalus rufescens from 

Senegal. Malimbus 7: 61-62. 
Eisentraut, M. 1963. Die Wirbeltiere des Kamerungebirges. Hamburg & Berlin. 
Elgood, J. H. 1958. A new species of Malimbus. Ibis 100: 621-624. 

— 1988. Rediscovery of Malimbus ibadanensis Elgood, 1958. Bull. Brit. Orn. CI. 108(4): 

Erard, C. 1991. Variation geographique de Bleda canicapilla (Hartlaub) 1854 (Aves, 

Pycnonotidae). Description d'une sous-espece nouvelle en Senegambie. L'Oiseau et 

R.F.O. 61:66-67. 
Erard, C. & Roux, F. 1983. La Chevechette du Cap Glaucidium capense dans l'Ouest 

africain. Description d'une race geographique nouvelle. L'Oiseau et R.F.O. 53: 

Forbes- Watson, A. D. 1970. A new species of Melaenornis (Muscicapinae) from Liberia. 

Bull. Brit. Orn. CI. 90: 145-148. 
Fry, C. H., Keith, S. & Urban, E. K. 1988. The Birds of Africa. Vol 3. Academic Press. 
Gatter, W. 1985. Ein neuer Bulbiil aus Westafrika (Aves, Pycnonotidae). Journal f. Orn. 

Giraudoux, P., Degauquier, R., Jones, P. J., Weigel, J. & Isenmann, P. 1988. Avifaune du 

Niger: etat des connaissances en 1986. Malimbus 10: 1-140. 
Grimes, L. G. 1987. The Birds of Ghana. British Ornithologists' Union, Tring, UK. 

G. J. Morel & C. Chappuis 224 Bull. B.O.C. 1 1 2A 

Heim de Balsac, H. & Mayaud, N. 1962. Les Oiseaux du Nord-ouest de VAfrique. 

P. Lechevalier, Paris. 
Howard, R. & Moore, A. 1980. A Complete Check-list of the Birds of the World. Oxford 

University Press. 
Jouanin, C. & Roux, F. 1963. Une race nouvelle de Heron cendre Ardea cinerea monicae. 

L'OiseauetR.F.O. 33: 103-106. 
Keith, S. & Gunn, W. W. H. 1971. Birds of African Rain Forests. Sounds of Nature No. 9. 

Federation of Ontario Naturalists, Don Mills Ontario (two 12 inch discs). 
Lamarche, B. 1980-1981. Liste commentee des oiseaux du Mali. Malimbus 1: 121-158; 2: 

— 1988. Liste commentee des oiseaux de Mauritanie. Etudes sahariennes et ouest- 

africaines. 1 , 4 et special. 
Louette, M. 1981. A new species of Honeyguide from West Africa (Aves, Indicatoridae). 

Revue Zool. Afr. 95: 131-135. 
Mackworth-Praed, C. W. & Grant, C. H. B. 1970. Birds of West Central and Western Africa. 

African Handbook of Birds. Series 3, Vol. 1. Longman. 
Mahe, E. 1985. Contribution a l'etude scientifique de la region de Banc d'Arguin. 21°20'N/ 

19°20'N. Peuplements avifaunistiques. 2 fascicules. These Acad. Montpellier. 575 pp 

and 56 pp. 
Morel, G. J. & Morel, M-Y. 1989. Une heronniere mixte sur le lac de Guier (Senegal) avec 

reference speciale a Ixobrychus m. minutus et Platalea leucorodia. L'Oiseau et R.F.O. 59: 

Morel, G. J. & Roux, F. 1962. Donnees nouvelles sur l'avifaune du Senegal. L'Oiseau et 

R.F.O. 32: 28-56. 
— , — 1966. Les migrateurs palearctiques au Senegal. Terre et Vie 20. 1. Non- 

passereaux: 19-72; Passereaux et synthese generale: 143-176. 
Naurois, R. de. 1966. Le Heron pourpre de l'archipel du Cap Vert, Ardea purpurea bournei 

ssp. nov. L'Oiseau et R.F.O. 36: 89-94. 
Naurois, R. de & Roux, F. 1974. Precisions concernant la morphologie, les affinites et la 

position systematique de quelques oiseaux du Banc d'Arguin (Mauritanie). L'Oiseau et 

R.F.O. 44: 72-84. 
Payne, R. B. 1977. Juvenile plumage of Cuculus canorus and Cuculus gularis in Africa. Bull. 

Brit. Orn. CI. 97: 48-54. 

— 1 982. Species Limits in the Indigobirds (Ploceidae, Vidua) of West Africa : Mouth Mimicry, 

Song Mimicry, and Description of New Species. Museum of Zoology, University of 

Michigan, No 162. Ann Arbor. 
Serle, W. 1959. Note on the immature plumage of the Honey-guide Melignomon zinkeri 

Reichenow. Bull. Brit. Orn. CI. 79: o 65. 
Smith, E. F. G., Arctander, P., Fjeldsa, J. & Amir, O. G. 1991. A new species of shrike 

(Laniidae: Laniarius) from Somalia, verified by DNA sequence data from the only 

known individual. Ibis 133: 227-235. 
Snow, D. W. 1978. An Atlas of Speciation in African Non-Passerine Birds. British Museum 

(Natural History), London. 
Urban, E., Fry, C. H. & Keith, S. 1986. The Birds of Africa. Vol. 2. Academic Press. 
Van der Weyden, W. J. 1973. Vocal affinities of the African and European Scops Owls Otus 

scops (Strigidae). Bull. IF AN. 35 ser. A, No. 3: 716-722. 
White, C. M. N. 1960. A Check List of the Ethiopian Muscicapidae (Sylviinae). Part 1 . Occ. 

Pap. Nat. Mus. Southern Rhodesia: 704-707. 

— 1 965 . A Revised Check List of African Non-Passerine Birds. Government Printer, Lusaka. 

Addresses: Dr Gerard J. Morel, 1, route de Sallenelles, 14860 Breville-les-Monts, France. 
Dr Claude Chappuis, "Les Chardonnerets", Lotissement du Fer a Cheval, La Bouille, 
76530 Grand-Couronne, France. 

© British Ornithologists' Club 1992 




. * *•» T f f fit I I # r"t 


. c 

1 r\ 


# <* * m # 

€***• * 

2- ! 

1- ! 




1- I 

■ n 5 


* ^m\^HMMH vh ^ 

»*.*>* % % % n 


i t fi l ffi!\tUliilUVll Hill" I 

* * *. * M^M^MWWH'M 

I S 

Figure 1. Sonagrams (analysed in wide band, 300 hz) of Eupodotis species. Frequencies in 
Khz, time in sec. A— D: gindiana. A — song of $, B = segment of song of <$, C = immature, D = 
short phrase of <$. E-G: ruficrista = parts of song. H-K: savilei. H = song (of immature ?), I 
and K = song of adults, J = call note. In gindiana and ruficrista the structural similarity of 
notes and motifs in D, E, F and G support the opinion that they are conspecific: the phrase 
begins with a note which progressively turns into a motif. The rhythm shows no acceleration. 
In savilei the initial note remains unchanged throughout the phrase but the rhythm increases 








2 CM 

CO CM t- 

3 'c 


1 2 


0,2 5 




Figure 3. Comparison of an isolated call in 2 Stizhorina (each analysed on a different scale). 
A—fraseri, on a frequency scale of 0-16 Khz; duration of cry c. 0.135 sees. B=finschi, on a 
scale of 0-8 Khz, but with a doubled time scale; duration of cry c. 0.35 sees, i.e. more than 
double that of fraseri. 

Figure 4. Song of Prinia subflava from western and eastern Africa. A, B, C from Nigeria. E, 
F, G from Kenya. The fast rhythm of F indicates territorial flight song. The fine striations of 
notes, a specific character, are not always visible on sonagram copies. 



. i^f i^ Hf H/ 


\ I ll 


: i "i "i *i 

■ F 

: 11 M H 


^ "ft -H «H 

' i if 1/ 1/ 1/ 


- -* '^u L* i^u 
■'Ml Ml 

i i i i 


" V flj 4J 41 

Mr "1 1 'V 

- <r ?f »l *r 


Figure 5. Song comparison of Prima fluviatilis and P. subflava : fluviatilis = A (Chad), B 
(Niger), C and D (NW Senegal); subflava = E (Kenya), F and G (Chad), H (N Senegal). In 
subflava the main volume is delivered on one note, with fast variations of frequency on a 
broad segment; in fluviatilis this variation is small and slow. 


.(- 1 

;; JA 





H / A 

" 3 



' 4 


A* A* 

/U ta A* 

■ ... i 

•• 5 


i • 

N / / 

• • 

Figure 6. Songs of 4 Apalis males (frequency scale from 160 to 16,000 Hz). 1 = rufogularis , 
S. Cameroun; 2 and 3=sharpii, Ivory Coast; 4=goslingi, Gabon; 5 — bamendae, S. W. 
Cameroun. Two groups of rhythm appear: (1) 4-6 notes per second: A. goslingi and A. 
bamendae. These 2 species differ from each other by the scale of variation of frequencies. 
(2) 2.5-3.2 motifs per second: A. rufogularis and A. sharpii, which present considerable 
similarity in the structure of the notes and the motifs. 

H. Ouellet 


Bull.B.O.C. 112A 


Summary of species included in the genus Sporophila by various authors: A = Ridgely 

& Tudor (1989); B = Morony, Bock & Farrand (1975); C = Paynter & Storer (1970); 

D = Sibley & Monroe (1990); E = Meyer de Schauensee (1952); F = Wolters (1980); 

G = Hellmayr (1938). The asterisk (*) indicates a species listed by a given author. 









collar is 






















































zelichi b 




































































Number of species 








'allospecies of lineola. 

2 a subspecies of nigricollis. 

^allospecies of minuta. 

4 a subspecies of minuta. 

s allospecies of cinnamomea. 

'described in 1977 (see Narosky 1977). 

7 not in the range of the work of these authors. 
8 placed in genus Tiaris by these authors. 
9 cf. americana 
l0 cf. palustris. 
"cf. bouvreuil. 

S. torqueola included. The taxa, as listed by each author, are summarized 
in Table 1 . 

The status of S. bouvronides has fluctuated between that of a subspecies 
of S. lineola (Meyer de Schauensee 1952, Paynter & Storer 1970, Morony 

Bull.B.O.CAUA 227 Sporophila 

et al. 1975, Wolters 1980) to that of a species (Hellmayr 1938, Schwartz 
1975, Ridgely & Tudor 1989), and more recently as an allospecies of S. 
lineola (Sibley & Monroe 1990); but the relationship of bouvronides and 
lineola remains unclear. Hellmayr (1938), on the other hand, had treated 
S. ardesiaca as a subspecies of S. lineola, although it is presently recog- 
nized as a species by most authors; but Meyer de Schauensee (1952) did 
not include it in his revision and it may prove to be a hybrid (Sick 1962, 

Hellmayr (1938) placed *S\ peruviana in the genus Neorhynchus which 
was considered later to be congeneric with Sporophila (Meyer de 
Schauensee 1952). 

Hellmayr (1938) listed S. hypoxantha as a subspecies of S. minuta. 
Meyer de Schauensee (1952) considered S. hypoxantha to be conspecific 
with S. minuta, and S. hypochroma with S. castaneiventris. Wolters (1980) 
on the other hand regarded S. ruficollis as conspecific with S. hypoxantha. 
Most recently Sibley & Monroe (1990) consider S. hypoxantha to be an 
allospecies of S. minuta, and S. hypochroma to be an allospecies of 
S. cinnamomea. 

S. zelichi was not described until 1977 (Narosky 1977) and was 
consequently included only in classifications published after that date. 

S. obscura has been classified until recently in the genus Sporophila 
by most authors, but has been transferred latterly to the genus Tiaris 
(Ridgely & Tudor 1989, Sibley & Monroe 1990) on the basis of earlier 
recommendations (Collins & Kemp 1976, Clark 1986). S. aurita, lorenzi 
and saturata, valid species in Hellmayr (1938), were synonymized 
respectively as S. americana, palustris and bouvreuil by other authors 
(Table 1). 

Olson (1981a), in reviewing characters of the genus Oryzoborus, con- 
sidered the shape of the bill to have little taxonomic value at the generic 
level and recommended that Oryzoborus be considered congeneric with 
Sporophila. This recommendation has not been followed so far, but, 
should it be adopted, the genus Sporophila would thus include 5 ad- 
ditional species: Oryzoborus nuttingi, crassirostris, atrirostris, maximiliani 
and angolensis, as listed in recent works (Ridgely & Tudor 1989, Sibley & 
Monroe 1990). 

Colours and colouration patterns 

Ridgely & Tudor (1989) divided the genus Sporophila into 7 distinct 
groups based on plumage colouration and patterns, an arrangement 
apparently designed primarily for field identification purposes and not 
essentially for taxonomic reasons. In Fig. 1, for taxonomic purposes I 
have divided the species of the genus Sporophila, including obscura, into 
plumage types based on the affinities of colour or colouration patterns in 
males; they show the extensive variation in colours or colouration 
patterns found in the genus and represent 5 distinct groups. This 
approach is highly artificial, but allows the grouping of species into 
smaller more meaningful units for comparative purposes. Although I am 
uncertain about the value of such an approach, it clearly indicates external 
character affinities between groups and the members of groups, or even 
between the genus Sporophila and other closely related genera. 

H. Ouellet 


Bull.B.O.C. 112A 

Figure 1 . The genus Sporophila, separated into 5 groups (Types) based on the colour or 
colouration patterns of males. Each 'Type' depicts a typical species, followed by the other 
species assigned to this group. Type I. Mostly black and white or buff: lineola — bouvronides, 
americana (including aurita), collaris and torqueola. Type II. Black facial mask or hood: 
nigricollis — ardesiaca, melanops, luctuosa and obscura (Tiaris). Type III. Uniform grey 
or buff upper parts: intermedia — caerulescens, peruviana, albogularis, schistacea, plumbea, 
falcirostris, leucopter a, frontalis and simplex. Type IV. Cinnamon, chestnut or rusty under 
parts: minuta — bouvreuil, hypoxantha, hypochroma, nigrorufa, castaneiventris, cinnamomea, 
palustris, ruficollis, zelechi and melanogaster (black under parts). Type V. Streaked upper 
parts and white at base of tail: telasco — insulata. The illustrations were prepared by Michel 

Plumage and colouration patterns are highly variable in some members 
of the genus, as illustrated by the extensive geographic variation 
reported in 2 well studied species: S. torqueola (Monroe 1968, Meyer de 
Schauensee 1952) and S. americana (Olson 1981b, Meyer de Schauensee 
1 952). I have placed S. [ Tiaris] obscura in Type II and S. simplex in Type 
III, although the colouration of these birds does not suggest straightaway 
such an arrangement because the dominant colour appears to conceal a 
less obvious colouration pattern. The principal merit of this arbitrary 
arrangement is to assemble into homogeneous groups species that appear 
to share several external morphological features. 


Seedeaters are in general small and never attain the large body 
dimensions of many Emberizines. Using wing length as a general 
indicator of body size, wings (chord) range from 52 to 66 mm in males, the 
females being slightly smaller. The bill (exposed culmen) of males varies 

Bull.B.O.C. 112A 



Measurements, in mm, for wing chord and exposed culmen of species in the 
genus Sporophila. Numbers in parentheses show the sample size and are 
followed by the mean and standard deviation of the mean. Numbers in square 
brackets indicate data obtained from Meyer de Schauensee (1952), Hellmayr 
(1938) and Short (1969). 









58.2 + 1.99 


7.4 + 0.38 




53.7 + 2.11 


7.6 + 0.28 


americana 2 




9.9 + 0.53 








55.3 + 1.99 


8.2 + 0.37 












56.7 + 1.29 








8.5 + 0.46 
















62.0 + 0.72 


9.8 + 0.32 




56.6 + 2.19 


9.9 + 0.44 








plumbea 5 


58.1 + 1.28 


9.2 + 0.47 










61.2 + 2.2 


11.2 + 1.02 






8.2 + 0.35 
















minuta 6 


50.8 + 1.63 


7.9 + 0.36 


















49.6 + 1.46 


7.6 + 0.52 






















torqueola 1 


51.9 + 1.5 


8.4 + 0.51 


obscura 8 




8.8 + 0.81 

{ S.l.lineola. 

s S.p.whiteleyana. 

2 S.a 


6 S.m.minuta. 

3 S.s 


n S.t.morelleti. 



8 S.o.obscura. 

from 5.6 to 13.0 (15?)mm (Table 2), females again being somewhat 
smaller. It is interesting to note that nearly all the larger species generally 
belong to Type I (Fig. 1), that the smaller ones fall in Type II, and that the 
species of intermediate size are distributed among the other 3 plumage 
types. Although species with a more brightly coloured plumage appear 
more frequently to have smaller body dimensions, this correlation may be 
purely coincidental and appears to have no adaptive or evolutionary 

H.Ouellet 230 Bull. B.O.C. 11 2A 

Sexual dimorphism 

Sexual plumage dimorphism is well marked in the genus Sporophila, 
the males of most species having a conspicuously more colourful or 
contrasting plumage in comparison with the dull beige female plumage. 
However, intersexual plumage differences are slight in a few species, such 
as obscura, simplex and frontalis. The drab female plumages, generally 
without obvious distinctive traits, make species identification often 
difficult or impossible even for some birds in the hand. Sexual size 
dimorphism is less noticeable, but females have in general smaller 
(il5° ) body dimensions, with wing and tail lengths showing most 
difference and tarsus and culmen lengths least. 


In Table 3 I have listed the monotypic and polytypic species of the genus 
Sporophila. Nineteen species are monotypic and show so little geographic 
variation that no subspecies is currently recognized in any of them. 
Fourteen species are polytypic with 2 or more accepted subspecies, 
although the taxonomic status of some of them is dubious pending re- 
views of their status based on new material. The extent of individual and 
geographic variation, as well as the characteristics and distribution of 
many subspecies, remain incompletely studied. Detailed revisions are 
now necessary to understand clearly the evolution of this group, because 
most of the work on this aspect has been done at a time when less extensive 

List of monotypic and polytypic species in the 
genus Sporophila. Numbers in parentheses show 
the number of currently recognized subspecies. 



Monotypic species 

Polytypic species 




lineola (2) 


americana (7) 


collaris (3) 


nigricollis (3) 


caerulescens (3) 


peruviana (2) 


schistacea (4) 


intermedia (4) 


plumbea (3) 


leucoptera (4) 


bouvreuil (4) 


minuta (3) 


torqueola (5) 


obscura (4) 






Bull.B.O.C. 112A 



material was available than it is now and when the criteria for subspecific 
recognition were different. 

The problems resulting from intergeneric and interspecific hybridiz- 
ation have been recognized for some time (Lordello 1957, Sick 1963) 
but have not been studied or assessed adequately in many instances. 
Consequently, the validity or the relationships of several taxa, especially 
S. hypoxantha, hypochroma, insulata, palustris, zelichi, lineola and 
bouvronideSy remain in doubt. The access to new information and material 
and the use of new techniques should foster a fresh understanding of 
geographic variation and permit a critical evaluation of the status of 
subspecies, as well as interspecific and intergeneric relationships. 


General distribution 

The genus Sporophila is primarily a South American taxon, but 
representative species occur on both sides of the equator from southern 
Texas (Rio Grande Valley) in the United States (S. torqueola) (American 
Ornithologists' Union 1983) through Central America south to southern 
Argentina (S. caerulescens and S. ruficollis) (Paynter & Storer 1970, 
Ridgely & Tudor 1989, Sibley & Monroe 1990). Species diversity is least 
at the northern and southern extremities of the range of the genus and 
attains its maximum between 10°N and 30°S (Fig. 2). This area forms a 
vast and ecologically diversified continental region with a complex 
evolution and history (Haffer 1985, 1987) in which the distribution and 
evolution of the genus Sporophila remain uninterpreted. Few of its 
species have colonized islands (Meyer de Schauensee 1952) and only one, 



45 40 35 30 25 20 15 10 5 5 10 15 20 25 30 35 40 45 


Figure 2. Diagram showing the number of species in the genus Sporophila recorded at 
various latitudes, north and south of the equator, compiled from the sources listed in Table 
1 . The number at the top of each bar represents the number of species occurring in a band of 
5° latitude. 

H. Ouellet 



































232 Bull.B.O.C. 11 2A 

Sympatryin Sporophila species 

















30 3S 


Figure 3. Diagram showing the species of the genus Sporophila and the number of species 
with which each species is sympatric. 

S. insulata, has been found to be endemic and either allopatric or 
parapatric pending a review of its taxonomic status. 

Sympatric species 

All Sporophila species, with the exception of insulata, are sympatric 
with 3 or more congeners (Fig. 3). The totals in Fig. 3 are based on the 
number of taxa with which a given species is sympatric in any part of its 
range, even in a small portion of it. Most species are sympatric with less 
than 10 congeners, and only a few with a large number of congeners. S. 
nigricollis, caerulescens, plumbea, ruficollis, collaris, leucoptera, luctuosa, 
bouvreuil and hypoxantha present the highest incidence of sympatry in the 
genus. Such a situation is seemingly the result of their extensive, often 
nearly continental, distributions. Equally important is the fact that these 
distributions, or parts thereof, fall in the sector where the greatest species 
concentration has been recorded, between 10°S and 20°S (Fig. 2). 
Although these preliminary results are as accurate as possible at this 
time, they are likely to be modified significantly when new data become 

Zoogeographic 'rules' 

There appear to be no obvious examples of Bergmann's or Gloger's 
ecogeographic rules among the polytypic species of the genus Sporophila. 
Graves (1991) has recorded clines in the body size of Andean Diglossa 
and only an equally careful analysis of body size, as well as a careful 
examination of colouration, will allow a verification of these principles in 
Sporophila, particularly in those species with extensive ranges. 

Bull.B.O.CA12A 233 Sporophila 

Sick (1991: 40) recently stated: "The Biscutate Swift is one more 
example from South America of the tendency for populations near the 
equator to be smaller in size than those at higher latitudes". He cites 
several examples including one in the Emberizinae, Oryzoborus 
angolensis, to illustrate his findings and adds that "Such geographical 
variation warrants recognition in the nomenclature" (Sick 1991). Sick's 
Rule, as this phenomenon may be designated, has yet to be demonstrated 
in the polytypic species of the genus Sporophila, although there are vague 
indications that populations of some of its species may have slightly 
smaller body dimensions near the equator; but the adaptive or evolution- 
ary implications of this hypothesis need yet to be demonstrated and 

Taxonomic problems 

Taxonomic questions associated with the genus Sporophila are numer- 
ous and complex and take place at 3 levels: higher categories, genus and 
species. Recent proposals support inspiring theories but have provided 
few answers to long standing problems. 

Higher categories 

The history of the higher categories to which the genus Sporophila 
has been associated has been summarized in Sibley & Ahlquist (1990). 
Based on evidence resulting from DNA-DNA hybridization studies, they 
conclude that seedeaters are closely related to typical tanagers (Bledsoe 
1984, Sibley & Alquist 1990: 683). The genus Sporophila has thus been 
classified in the Tribe Thraupini, Subfamily Emberizinae, Family 
Fringillidae (Sibley & Alquist 1990, Sibley & Monroe 1990). This 
classification diverges significantly from more traditional ones where the 
genus Sporophila is placed in the Family Emberizidae and Subfamily 
Emberizinae (Paynter & Storer 1970, Morony et al. 1975, American 
Ornithologists' Union 1983), and it requires corroboration based on the 
analysis of a wider selection of taxa, particularly those that were not 
included in the DNA comparisons, before it can be adopted universally. 

The genus 

Ridgway (1901) gave a detailed summary of the characteristics of the 
genus Sporophila and pondered over the great differences found between 
several species included in it. A genus like Sporophila, which incorporates 
a large number of morphologically different species, is not likely to 
generate unanimity among taxonomists unless solid criteria are selected 
for defining its limits. Morphological characters presently need to be 
reassessed and compared with the biochemical and genetic information 
that will ensue from future studies before a more stable systematic basis 
can be established for this genus and the other closely related genera. In 
the interim, the relationships between Sporophila and other genera re- 
main uncertain; for example, the genera Dolospingus, Oryzoborus, Tiaris, 
Volatinia and Loxigilla are among those which, in addition to sharing 
many morphological characters found in Sporophila, may prove to be 
even more closely related than is suspected. 

H. Ouellet 234 Bull. B.O.C. 1 12A 

The species 

A large proportion of the species of the genus Sporophila are generally 
accepted and are, for the most part, well defined, but the situation is more 
ambiguous for a few of them (Table 1 ) and several categories of taxonomic 
problems can be identified at the species level. Four currently recognized 
species may eventually be treated as hybrids whose origin is practically 
unknown: ardesiaca (Sick 1962, 1963), melanops, insulata and zelichi 
(Vuilleumier & Mayr 1987, Ridgely & Tudor 1989). Other species may 
eventually be treated as subspecies of other clearly identified taxa like 
bouvronides [lineola], ardesiaca [nigricollis], insulata [telasco or minima] 
and hypoxantha [minuta]. Oppositely, the nominate S. leucoptera (includ- 
ing S. I. cinereola) and S. I. bicolor may be 2 separate species, as indicated 
by Ridgely & Tudor (1989) rather than 2 subspecies. Similar situations 
prevail in other species such as S. intermedia and lineola and require 
additional study. Yet a few others may be nothing more than colour 
morphs or aberrant individuals of other taxa: ardesiaca [nigricollis], 
melanops [nigricollis] (Ridgely & Tudor 1989), hypochroma [cinnamomea], 
palustris [hypoxantha], ruficollis [hypoxantha] (Short 1969, 1975) and 
zelichi [cinnamomea]; while some have been treated recently as allo- 
species of superspecies: bouvronides [lineola], hypoxantha [minuta] and 
hypochroma [cinnamomea] (Sibley & Monroe 1990). Thus, the variety of 
taxonomic opinions and treatments given to the taxa of this genus, makes 
it essential to acquire additional morphological, ecological and behav- 
ioural information, as well as biochemical and genetic data, to determine 
their status and affinities. 


Much work remains also to be done at the subspecies level. Geographic 
variation has been thoroughly studied in only a few species like S. 
americana (Olson 1981b) and the definition, status and distribution of 
many others is incompletely known. The polytypic species, particularly 
those with widely disjunct populations like S. plumbea, and those with a 
wide distribution, need to be reviewed and geographic variation assessed 
in the light of new material and techniques. 


American Ornithologists' Union. 1983. Check-list of North American Birds. Sixth Edition. 

Washington, D.C.: American Ornithologists' Union., pp. i-xxix, 1-877. 
Bledsoe, A. H. 1984. The phylogeny and evolution of the New World nine-primaried 

Oscines as indicated by DNA-DNA hybridization. Yale University, Doctoral 

Dissertation: i-viii, 1-155. 
Clark, G. A. 1986. Systematic interpretation of foot-scute patterns in Neotropical finches. 

Wilson Bull. 98(4): 594-597. 
Collins, C. T., & Kemp, M. H. 1976. Natal pterylosis of Sporophila finches. Wilson Bull. 

88(1): 154-157. 
Graves, G. R. 1991. Bergmann's rule near the equator: latitudinal clines in body size of an 

Andean passerine bird. Proc. Natl. Acad. Sci. U.S.A. 88: 2322-2325. 
HafTer, J. 1985. Avian Zoogeography of the Neotropical Lowlands. Ornith. Monog. 36: 

HafTer, J. 1987. Biogeography of Neotropical Birds. In: T. C. Whitmore and G. T. Prance 

(eds): Biogeography and Quaternary History in Tropical America. Oxford: Clarendon 

Press, pp. 105-150. 
Hellmayr, C. E. 1938. Catalogue of birds of the Americas and the adjacent islands in Field 

Museum of Natural History. Field Mus. Nat. Hist. Zool. Ser. 13 (11): 1-662. 

Bull.B.O.CA\2A 235 Sporophila 

Lordello, L. G. E. 1957. Duas aves hibridas da fauna do Brasil. Rev. Brasil. Biol. 17(1): 

Meyer de Schauensee, R. M. 1952. A review of the genus Sporophila. Proc. Acad. Nat. Sci. 

Philadelphia 54: 1 53-196. 
Monroe, B. L., Jr. 1968. A Distributional Survey of the Birds of Honduras. Ornithological 

Monographs No. 7: 1-458. 
Morony, J. J., Jr., Bock, W. J. & Farrand, J., Jr. 1975. Reference List of the Birds of the World. 

New York: American Museum of Natural History, pp. i— x, 1-207. 
Narosky, S. 1977. Una nueva especie del genero Sporophila (Emberizidae). El Hornero 

11(5): 345-348. 
Olson, S. L. 1981a. A revision of the subspecies of Sporophila ('Oryzoborus') angolensis 

(Aves: Emberizinae). Proc. Biol. Soc. Washington 94(1): 43-51. 

— 1981b. The nature of the variability in the Variable Seedeater in Panama (Sporophila 

americana: Emberizinae). Proc. Biol. Soc. Washington 94: 380-390. 
Paynter, R. A., Jr. & Storer, R. W. 1970. Check-list of Birds of the World. Volume 13. 

Cambridge: Museum of Comparative Zoology, pp. i-xiv; 1-443. 
Ridgely, R. S. & Tudor, G. 1989. The Birds of South America. Volume 1. The Oscine 

Passerines. Austin, Texas: University of Texas Press, pp. 1— xvi, 1-516. 
Ridgway, R. 1901. The Birds of North and Middle America. Part 1. Bull. U.S. Nat. Mus. 50: 

i— xvii, 1—715; plates. 
Schwartz, P. 1975. Solved and unsolved problems in the Sporophila lineolajbouvronides 

complex (Aves: Emberizidae). Ann. Carnegie Mus. 45(14): 277-285. 
Short, L. L., Jr. 1969. Relationships among some South American seedeaters (Sporophila), 

with a record of S. hypochroma for Argentina. Wilson Bull. 81(2): 216-219. 

— 1975. A zoogeographic analysis of the South American Chaco avifauna. Bui. Amer. Mus. 

Nat. Hist. 154(3): 16^352. 
Sibley, C. G. & Ahlquist, J. E. 1990. Phylogeny and Classification of Birds: a study in 

Molecular Evolution. New Haven, Connecticut: Yale University Press, pp. i-xxiii, 

Sibley, C. G. & Monroe, B. L., Jr. 1990. Distribution and Taxonomy of Birds of the World. 

New Haven, Connecticut: Yale University Press, pp. i-xxiv, 1-1 111. 
Sick, H. 1962. Reivindicacao do papa-capim Sporophila ardesiaca (Dubois). Sua ocorrencia 

no Brasil (Fringillidae-Aves). Bol. Mus. Nac. Nov. Ser. Rio de Janeiro — Brazil 235: 


— 1963. Hybridization in certain Brazilian Fringillidae (Sporophila and Oryzoborus). Proc. 

XHInternat. Ornithol. Congr. 1962 1: 161-170. 
— 1991 . Distribution and subspeciation of the Biscutate Swift Streptoprocne biscutata. Bull. 

Brit. Orn. CI. 111(1): 38-40. 
Vuilleumier, F. & Mayr, E. 1987. New species of birds described from 1976 to 1980. ^. 

Ornithol 128(2): 137-150. 
Wolters, H. E. 1980. Die Vogelarten der Erde. Volume 5. Berlin: Paul Parey, pp. 321-400. 

Address: Dr. Henri Ouellet, Canadian Museum of Nature, P.O. Box 3443, Station «D», 
Ottawa, Canada. KIP 6P4. 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 237 E. N. Panov 

Emergence of hybridogenous polymorphism in 
the Oenanthe picata complex 

by E. N. Panov 

Received 14 May 1992 

The simultaneous existence in a population of 2 or more discrete pheno- 
types ('morphs', 'phases', 'varieties') belonging to one sex and age-class 
(e.g. sexually mature males) is generally known as genetic polymorphism. 
Although polymorphism of this kind is by no means rare in birds, many 
questions concerning the causal relationships and biological significance 
of the phenomenon remain open. One such question concerns the 
mechanisms by which polymorphism originates within a population. 

Alongside the prevailing view that polymorphism is caused by a pro- 
cess of mutation (i.e. spontaneous events taking place purely within a 
given population), the idea has also been expressed that it may have 
evolved on the basis of gene exchange between originally independent 
populations (see e.g. HafTer 1977: 41). 

In this paper an attempt will be made to reconstruct the historical 
process which led to 'hybridogenous polymorphism' (see Panov 1989), 
and other types of variation resulting from hybridization, in Palaearctic 
wheatears of the Oenanthe picata complex. Until recently, geographical 
variation in this complex was generally treated as a variation in the relative 
numbers of 3 colour 'varieties' or 'morphs' {picata, capistrata and opistho- 
leuca). The origin of this supposedly discrete variation was seen in terms 
of changes in the frequency of alleles of certain genes responsible for male 
plumage coloration (e.g. Mayr & Stresemann 1950, Paludan 1959, Loskot 
1972, Stepanyan 1978). 

Our hypothesis (Panow 1974, Panov 1989) is based on a completely 
different premise, namely that the 3 plumage types in the Eastern Pied 
Wheatear O. picata in fact characterize 3 originally independent taxa, 
each of which evolved in its autochthonous range in accordance with the 
principles of geographical speciation. The present distribution pattern of 
individuals with the 3 different plumage types (and also of various 'inter- 
mediate' phenotypes) is explained by the processes whereby the gene 
pools of the 3 original populations became intermixed. 

We shall examine here the 3 main types of integration processes which 
correspond to the varying nature and intensity of gene flow between 
erstwhile independent population systems. 

1 . Limited hybridization in places where the breeding ranges of the 
original forms abut (parapatry) or overlap to an insignificant extent 
(allo-parapatry). The result may be the formation of a narrow zone of 

2. Prolonged existence of such a zone may lead to the establishment of 
gene flow from the zone of hybridization into the ranges of the parent 
forms. Gene migration takes place through the generations and also 
through dispersal by individuals of one form into the range of another and 
by birds of hybrid origin straying into the ranges of both forms. 

E. N. Panov 238 Bull. B.O.C. 1 1 2A 

3. Should hybridization become more firmly established, the hybrid 
zone may expand and a panmictic hybridogenous population with poly- 
morphic features be created, which will eventually acquire a range of its 

In the years 1966-1990, we studied the phenotypic composition of 
Eastern Pied Wheatear populations at 10 localities in the bird's Central 
Asian breeding range. A total of 279 males and 168 females was trapped, 
and 347 chicks were individually marked, 34 of these being retrapped in 
subsequent years. Twenty-eight chicks were reared in captivity until they 
had acquired adult plumage, and 296 specimens (217 males, 79 females) 
were examined in museum collections. 

Divergence within the 'Eastern Pied Wheatear* complex 

Plumage colour and sexual dimorphism 

The 3 forms which constitute this complex were originally described as 
independent species under the names Saxicola picata Blyth, 1847, »S. 
opistholeuca Strickland, 1849, and S. capistrata Gould, 1865. They are 
well differentiated in plumage coloration, not only of males but also 
females (Fig. 1) and, perhaps, also in juvenile plumage (Zarudnyi 1923). 

Unlike the 2 others, the form capistrata shows clear sexual dimorphism, 
females being distinguished from males by the complete absence of 
melanins in their plumage. In the forms picata and opistholeuca, female 
plumage is variable, and females which are virtually indistinguishable 
from males are not uncommon (Panov 1989) (Fig. 2). There is some basis 
for the supposition that the contrasting male-type plumage is acquired by 
female picata and opistholeuca with age (Panov et al. in press). 


In those parts of its range where it is not in contact with the other 2 
forms, picata has a significantly shorter wing than populations from the 
autochthonous ranges of capistrata and opistholeuca. Maximum wing- 
length tends to be characteristic of populations from northern parts of the 
autochthonous range of capistrata, far from the ranges of the other 2 
forms (Table 1 ; see also Panov et al. in press). Wing-length in this case is 
probably a reliable indicator of general body-size. 

The weight of picata males from various localities in Turkmenistan 
ranges from 1 9.7 + 0.2 g to 21.5 + 0.4g (mean of whole sample of 102 
males 20.2 + 0.2 g). Similar values are quoted by Desfayes & Praz (1978) 
for southern Iran. Our sample of picata males differs significantly (t = 
4.69, P < 0001 ) from a sample of 6 males from the autochthonous range of 
capistrata (23.3 + 0.6 g). The latter value matches weight data for 10 
capistrata males (23.5 + 0.5 g) from northern Afghanistan (see Paludan 
1959). Further data in Paludan (1959) indicate a mean weight of 21.7 + 
0.4 g for 8 /)*Vflta males from western Afghanistan, and 22- 1 +033 gfor 10 
opistholeuca males from the autochthonous range of that form; the differ- 
ences between capistrata and picata are significant (/ = 3.1, P<001), also 
those between capistrata and opistholeuca (t = 2A, P<005); between 
picata and opistholeuca the differences are not significant (t = 0.77). 

Bull.B.O.C. 112A 


Oenanthe picata complex 

Figure 1 . Ranges of the form (a) picata (b) opistholeuca, (c) polymorphic hybridogenous 
population 'capistrata x opistholeuca' and (d) hybrid population 'capistrata x opistholeuca' x 
opistholeuca. Main directions of dispersal by the form picata into the range of (e) opistholeuca 
and (f) by individuals of the capistrata pehnotype into the range of picata are indicated by 

Top row: 
Middle row: 
Bottom row: 

<$ capistrata 

<$ picata 
$ picata 

<$ evreinowi S opistholeuca 

9 evreinowi 

$ opistholeuca 
$ opistholeuca 

Decreasing body-size in the order capistrata — opistholeuca — picata is 
also reflected in the different egg dimensions. 

Eggs of pairs with capistrata males are significantly larger (in width) 
than eggs from clutches of the form picata in its autochthonous range 
(16.0 + 0.6, n = 62 and 15.5 + 0.09, w = 49, respectively; * = 4.55, 
P< 0-0002). Eggs of the form opistholeuca occupy an intermediate 
position in this parameter (15.7 + 0.10 mm, n = 3S). 

E. N. Panov 


Bull.B.O.C. 112A 


Means (mm) ± standard deviation, sample size and range (mm) of wing-length (unflattened 

chord) of Eastern Pied Wheatears, the Oenanthe picata complex, from autochthonous 

ranges of the forms picata, capistrata and opistholeuca 

Males > 1 year 

lst-year males 


Range of: 

90.4 + 0.2 (n=110) 

88.0 + 0.2 (« = 81) 

85.7 + 0.3 (n = 81) 


92.3 +0.3 (n = 24) 

90.3 + 0.5 (n = 10) 

87.1 +0.3 (n = 20) 


92.9 + 0.3 (« = 61) 

90.5+0.3 (w = 45) 

87.1 +0.3 (n = 38)** 

Comparison by 
Student's /-test 


f = 5.28,P=0.0001 

? = 4.22,P=0.0002 

* = 3.41,P=0.001 


j = 8. 10,P = 0.00001 

* = 6.51,P=0.00004 

* = 2.97,P=0.01 


f=1.53,P = 0.14(n.s.) 

* = 0.28,P=0.78(n.s.) 

* = 0.07,P = 0.96(n.s.) 

*Hybridogenous polymorphic populations 'capistrata x opistholeuca' . Analysis of com- 
bined sample comprising the phenotypes capistrata, opistholeuca and evreinowi (differences 
between samples of these phenotypes within this population group are not significant). 
**In this sample 24 females are from the southern part of the range of the populations 
investigated, where there is perhaps some influence from genes of the small form picata. 
Mean for 14 females from northern part of the range of 'capistrata x opistholeuca' popu- 
lations is 88.6 + 0.5 mm (difference from mean of females from autochthonous range of 
opistholeuca significant, £ = 2.49, P = 0.05). 

Communication behaviour 

We compared the vocalizations of the 3 forms of Eastern Pied 
Wheatears, the motor patterns of their communication behaviour and the 
organization of the main types of social interactions (Kostina & Panov 
1981, Panov 1989). As a whole, the communication systems of these 
forms are structurally identical, though their component elements are 
subject to considerable variation. Because of this, data presented here on 
apparent quantitative differences between some homologous components 
are best regarded as provisional. 

Of the 6 call- and 4 song-types characteristic of all 3 forms, differences 
were found in one call-type — in picata and capistrata (data for opistholeuca 
are insufficient for comparison) — and 2 song-types. Advertising song dif- 
fers most conspicuously from the general type in the form opistholeuca in 
its autochthonous range. 

The motor patterns of communication behaviour appear identical, 
apart from certain tendencies for variation in the frequency with which 
particular elements of the patterns are used by one or another of the 
3 forms. Comparison of the organization of behaviour during pair- 
formation found capistrata females to be more aggressive than picata 
females. Pre-copulatory interactions are very similar in the forms picata 
and opistholeuca, but they differ from those of capistrata, whose behaviour 
in this context is closer to Finsch's Wheatear O.finschii. 

Bull. B.O.C. 1 12A 241 Oenanthe picata complex 

Habitat and timing of breeding season 

The form capistrata inhabits arid low hills and clearly avoids nearby 
high-mountain massifs. In the area of the former USSR, it ascends as a 
breeding bird to altitudes of c. 1 500 m. The form opistholeuca is found up 
to 2000-2500 m in the Pamiro-Alay, with picata also ascending to that 
altitude from the south. In the mountains of southern Iran, picata breeds 
in the zone between 2100 and 2400 m, occasionally ascending to 2700 m 
(Desfayes & Praz 1978). Originally typical inhabitants of rocky mountain 
habitats, picata and opistholeuca are spreading into broken semi-desert 
terrain originally occupied by the form capistrata, with which they now 
hybridize. In these areas of secondary contact, individuals of all 3 
phenotypes nest side by side in the same habitats. 

The form capistrata is probably prevented from expanding into the 
high-mountain parts of the ranges occupied by the other 2 forms because 
of its characteristically early breeding season. Thus, the start of nest- 
building by capistrata has been recorded in southern Uzbekistan 
(c. 38°N) around 6-1 5 March, while at approximately the same latitude in 
Badkhyz (southeast Turkmenistan) picata does not begin nesting before 
5—12 April. During this period in the range of opistholeuca, near where it 
abuts capistrata, arrival of females and pair-formation are not yet 
concluded (for details see Panov 1989). 

Hybridization and its consequences within the 'Eastern Pied 
Wheatear' complex 

According to the proposed hypothesis, there exist within the complex at 
the present time 3 population groups with a relatively stable phenotypic 
appearance, and populations intermediate between them found in the 
areas where the ranges of the 3 population groups referred to above are 
contiguous, or overlap or both. The phenotypically stable populations are 
as follows: 

1 . Populations generally with the diagnostic features of the form picata 
(which has the largest area of distribution in western and southern parts 
of the range occupied by the whole O. picata complex: see Fig. 1). 
Throughout the range, birds with some white on the head (tendency 
towards capistrata phenotype) are common alongside typical males. 
Locally, the proportion of such 'aberrant' males reaches 70% (see below 
for details); 

2. Populations showing the diagnostic features of opistholeuca 
(Badakhshan and Hindu Kush). Within the range of these populations a 
few individuals of the picata phenotype occur (not more than 10%). 
While mixed pairs are evidently a quite common phenomenon (Panov 
1989: 87), males showing plumage features intermediate between 
opistholeuca and picata are extremely rare; 

3. Polymorphic hybridogenous populations 'capistrata x opistholeuca', 
which presumably now occupy the autochthonous range of the form 
capistrata. They are found in the northeast part of the range of the com- 
plex (Figs. 1, 3). Over the whole range of these populations, there is a 
generally stable ratio of the phenotypes capistrata (the overwhelming 
majority), opistholeuca, and birds of the extremely variable phenotype 

E. N. Panor 


Bull.B.O.C. 112A 

Bull. B.O.C. 1 1 2A 243 Oenanthe picata complex 

evreinowi, intermediate between these 2. In the south of the range, in 
sections contiguous with picata, are found small numbers of picata males 
and picata x capistrata hybrids (total 5.6-11.4%). 

In the contact zones of the last group of populations with the 2 others, 
live hybrid populations whose phenotypic composition is highly variable 
in space and probably also in time occur. Such populations are known 
from northeast Afghanistan (Paludan 1959), and from the interfluve of 
the Pyandzh and Kyzylsu in Tadzhikistan. In addition, a hybrid popu- 
lation may perhaps exist where the ranges of opistholeuca and picata meet 
in northeast Pakistan, and where the form capistrata also penetrates via 
large river valleys from the northwest (Ticehurst 1 922, Paludan 1959; see 

Below, we shall examine in more detail: (1) the situation in the range of 
the polymorphic hybridogenous population capistrata x opistholeuca; (2) 
the zone of hybridization found where the range of that population meets 
the autochthonous opistholeuca populations in Tadzhikistan; and (3) the 
introgression of capistrata genes from the polymorphic capistrata x 
opistholeuca population into the autochthonous range of picata in 
southern Turkmenistan. 

1 . Polymorphic hybridogenous populations 'capistrata x opistholeuca' 

These populations inhabit low hills in the east of Central Asia and 
northern Afghanistan — from the relict mountains ('Inselberge') of the 
Kyzylkum desert in the north to the northern foothills of the Paropamiz 
and Hindu Kush in the south. Throughout their range (which measures 
c. 750 m west to east by c. 200 km north to south), they are relatively 
monotypic in phenotypic composition: among males, the capistrata 
phenotype makes up 68-78% of different samples, and the opistholeuca 
phenotype and evreinowi — to all intents and purposes united in a single 
continuum of variability — from 17.5 to 32%. (The picata and picata x 
capistrata phenotypes are normally present only in the southernmost 
parts of the range of these populations— see above and Fig. 3.) 

It is quite remarkable that the polymorphism of male plumage color- 
ation is combined with the monomorphic plumage of females: practically 
all females show the same dull sand-coloured plumage type. Dark 
(brown-black) females of the opistholeuca type are virtually absent from 
the range of these populations. 

Data from the individual marking of birds in the northern range of 
these groups of populations (Darbaza settlement in southern Kazakhstan, 
north of Tashkent) indicate the absence of strict mate-selection on 

Figure 3. Proportions of different phenotypes (%%) in the autochthonous range of (a) 
opistholeuca, (b), in the range of a polymorphic population 'capistrata x opistholeuca' and (c) 
in a hybrid population 'capistrata x opistholeuca x opistholeuca' and (d) the range of the form 
picata. Male phenotypes: (e) opistholeuca, (f) evreinowi, (g) capistrata, (h) capistrata x picata, 
(i) picata. Places where the samples were obtained: 1 = Tadzhik Badakhshan (25 males), 2 = 
Pyandzh- Kyzylsu interfluve (62), 3 = Karatau mountains (14), 4 = Babatag mountains (27), 
5 = lower reaches of Sherabad river (128), 6 = Nuratau mountains (16), 7 = western foothills 
of Karzhantau mountains (192), 8 = relict mountains in Kyzylkum desert (Aktau, Tamdy- 
tau, Bukantau)(129). 












E. N. Panov 244 Bull. B.O.C. 1 1 2A 

plumage type. As may be seen from the table below, a female having a 
father of her own phenotype (e.g. capistrata) may select as a mate a male of 
a different phenotype: 

Phenotypes of Phenotypes of females' mates Total number 

females' fathers capistrata opistholeuca of pairs 

capistrata 8 2 10 

opistholeuca 3 2 5 

Total number of pairs 11 4 15 

Individual marking also showed that one and the same female may breed 
with males of different phenotypes in different years. 

Support for the hypothesis of genetic polymorphism comes from the 
inherited plumage characteristics of sons sired by fathers of known 
phenotypes. As follows from the table below, the progeny of a male of 
given phenotype may include males of a different phenotype: 

Phenotype of Phenotype of sons Total number 

fathers capistrata opistholeuca evreinowi of sons 

capistrata{\2) 14 

opistholeuca(A) 2 

evreinowi{A) 6 

Total number of sons 22 

Two of the 4 male evreinowi fathers had a plumage type intermediate 
between capistrata and opistholeuca; the 2 others were of the opistholeuca 
colour type, with only a slight tendency towards capistrata. 

It is interesting that males of different phenotypes may be present even 
within the same brood. In 2 cases we were able to trace the inherited 
colour pattern through more than one generation. In one such line, the 
son, his father and grandfather were of the same opistholeuca phenotype. 
In another case, a capistrata male having father and grandfather of 
the same phenotype paired and bred with a female whose father was an 
opistholeuca male. The progeny of this pair included 2 males, one of 
which was of the capistrata phenotype, the other evreinowi. 

The aforesaid allows the conclusion that the populations considered 
here represent a genetically homogeneous entity which we suppose to 
have arisen as a result of penetration by the form opistholeuca into the 
range of capistrata and long-term hybridization between them. It may 
well be that the form capistrata no longer exists at the present time as an 
independent genetic system. 

2. Hybrid population found where the polymorphic population 'capistrata 
x ophistholeuca' abuts the range of the autochthonous form opistholeuca 

In the southeast of western Tadzhikistan, in the interfluve of the 
Pyandzh and its tributary the Kyzylsu, studies were made on a transect 
(of c. 100 km) running from southwest to northeast between the foothills 
of the Karatau range on the east bank of the Kyzylsu and the eastern 
slopes of the Khazretishi mountains (Khirmandzhou settlement — see 
Lyubushchenko & Grabovskiy 1991, and Panov et al. in press). Between 

Bull. B.O.C. 112A 245 Oenanthe picata complex 

the Karatau and Khazretishi ranges lies the South Tadzhik depression 
with its single, completely isolated mountain Khodzhamumin. 

The population of the Karatau foothills is part of the polymorphic 
population described above: out of 14 males observed, 11 were of the 
capistrata and 3 of the evreinowi phenotype. At the opposite, northeast 
end of the transect (Khirmandzhou), all 18 males recorded were of the 
opistholeuca phenotype. This population occupies the extreme northwest 
section of the autochthonous opistholeuca range. 

In the area lying between the points named, on the southern and 
eastern edge of the South Tadzhik depression and on the slopes of Mt 
Khodzhamumin, a further 5 demes of 6-24 pairs were studied. The 
phenotypic composition of such demes is highly variable. Overall, the 
ratio of capistrata, opistholeuca and evreinowi phenotypes in these 5 demes 
was 25.8: 48.4: 24.8 (w = 62), which is significantly different from the 
composition of all populations from the range of the polymorphic entity 
' capistrata x opistholeuca' discussed above (ANOVA; F= 7.22-9.12, 

It is important also that here, unlike in the polymorphic population 
referred to, female plumage colour varies: alongside the predominant 
capistrata type, opistholeuca-type females also occur. We thus have 
before us a heterogeneous (in the genetic sense) hybrid population in 
which there has been no stabilization of a monomorphic female pheno- 
type such as is taking place in the hybridogenous polymorphic population 
'capistrata x opistholeuca' . 

Among the 96 males observed on the transect, 2 were picata phenotypes 
and 3 had plumage intermediate between picata and capistrata. Two out 
of 43 females were also of the picata plumage type. This small admixture 
of the picata phenotype (5.2% among males) is presumed to be the result 
of dispersal by individuals of this form from northern parts of the picata 
range lying not far to the south. 

3. Migration of capistrata genes into the autochthonous range of the form 

We assessed the proportion of picata-type males with some white on 
the head at 4 points on a transect leading along the northwest edge of the 
picata range in southern Turkmenistan. The easternmost point on this 
transect lies approximately 200-300 km from the contact zone of picata 
and 'capistrata x opistholeuca' populations in north-central Afghanistan 
(see Paludan 1959). The 3 other samples were collected at points 
separated from the first and one from another by distances of the same 
order (Fig. 4). The amount of white in male head plumage was scored 
on an 8-point scale: — pure picata phenotype, 7 — phenotypically pure 

It is clear from Fig. 4 that males with some white on the head are not 
uncommon throughout that part of the picata range investigated, and in 
some areas they even outnumber males of the pure phenotype. The cause 
of this plumage feature in picata populations may be: (1) the existence of 
homologous genes in populations of picata and capistrata; and (2) intro- 
gression of capistrata genes into the range of picata. In the latter case, the 
migration of genes may (a) proceed through the generations (owing to 

E. N. Panov 


Bull.B.O.C. 11 2A 


Figure 4. Proportion of males with different head colour (%%). Point 1 =Badkhyz (n= 16); 
Point 2 = central Kopet-Dag (n = 38); Point 3 — western Kopet-Dag (n — 33); and Point 4 = 
near Krasnovodsk (n = 57). Head colour scored on point-scale: = pure picata; 7 = pure 
capistrata, 1-6 = intermediate ('hybrid') phenotypes. a = records of picata on its northern 
range limit in Afghanistan (from Paludan 1959); b = westernmost records of capistrata 
phenotype males in the USSR; c = records of capistrata in northern Afghanistan (Paludan 
1959); d = records of breeding capistrata in the range of picata. In the histograms, the 
extreme left column (black) shows the proportion in the given sample of typical black- 
headed picata males (score 0). The white columns right of the black column are shown in 
order of increasing point score (1, 2, 3, and so on). 

back-crossing of hybrids, originating in the secondary contact zone of the 2 
forms, with representatives of picata populations from its autochthonous 
range), and (b) may result from dispersal by individuals of the form 
capistrata into the range of picata. 

None of these possibilities can be refuted, but we are inclined to sup- 
port the hypothesis of gene introgression and, as evidence in favour of 
supposition 2b, we can at least cite the case of a capistrata male paired and 
breeding successfully with a picata female in the central Kopet-Dag 
(point 3 in Fig. 4; see also Bel'skaya 1961). Furthermore, supposition 2a 
appears to be contradicted at first sight by an increase in the proportion 
of 'white-headed' males with increasing distance from the range of 

The latter circumstance may nevertheless be reconciled with the 
hypothesis of gene migration if one rejects the idea that the flow of alien 
genes across the range of picata is uniform in space and in time. In par- 
ticular, the dynamics of phenotypic composition may, in principle, be 
influenced not only by the distance separating a given population from the 

Bull. B.O.C. 1 12A 247 Oenanthe picata complex 

source of an alien gene pool, but also by the extent of its separation from 
other birds of genetically the same stock. In this regard, it is significant 
that the plumage feature of partial 'white-headedness' has its widest 
distribution in the western Kopet-Dag and in the low hills of the south- 
east Caspian region, where suitable picata nesting habitat is patchily 
distributed rather than uniformly as in the central Kopet-Dag. In 
semi-isolated demes inhabiting widely separated mountain ranges, new 
plumage features can become fixed comparatively quickly, such features 
in the present case having been introduced into the given deme by alien 
capistrata genes (for further details, see Panov et al. in press). 


According to the proposed scenario, the 'Eastern Pied Wheatear' com- 
plex is a standard polytypic species comprising 3 geographical races, all of 
which were originally monomorphic in respect of male plumage colour. 
These races separated off and diverged in conditions of geographical 
isolation and then, as a result of range expansion, entered into secondary 
contact and hybridization. 

It was precisely the mixing of the gene pools of the 3 originally 
autonomous population groups which determined that phenotypic dis- 
similarity in Eastern Pied Wheatears which is generally called 'poly- 
morphism'. In our view, this concept is, in its generally accepted sense 
(see e.g. Mayr & Stresemann 1950), not applicable to the case under 
investigation. In fact, what we have before us is either 'pseudo- 
polymorphism' (see Panov 1989), i.e. the simultaneous existence of 
representatives of 2 or 3 different taxa in the area of their secondary 
contact (as is the case, for example, in the Pyandzh-Kyzylsu interfluve), 
or 'hybridogenous polymorphism' which has arisen as a result of long-term 
introgressive hybridization (of the population 'capistrata x opistholeuca'). 

Taking this scenario as a whole, it may be assumed that the first stage in 
its development was the simultaneous separation of a single ancestral 
species into 3 population groups. One of these (the present-day picata) 
separated off in the Iranian highlands; the second (opistholeuca) in the 
western mountain regions of Central Asia; the third (capistrata) originally 
inhabited the lower parts of the western Gissaro-Alay mountains and 
adjoining areas. 

The latter scheme cannot completely accommodate a number of facts 
which (if they have been correctly interpreted) may indicate that the 
forms in question have attained different levels of divergence and, there- 
fore, may differ one from another genealogically (i.e. in evolutionary age). 
One gains the impression that picata and opistholeuca are most probably 
sister taxa, while capistrata stands somewhat apart. This supposition 
gains strength from the fact that picata and opistholeuca on the one 
hand and capistrata on the other differ with respect to the type of 
sexual dimorphism, particular features of communication behaviour, and 
preferred habitats. 

After consideration of the foregoing, one may imagine 2 ways in which 
the Oenanthe picata complex may have emerged. The first option envisages 
a single ancestral form originally splitting into 2 population groups which 

E. N. Panov 248 Bull. B.O.C. 1 12A 

may provisionally be called 'low-mountain' and 'high-mountain'. The 
first group eventually produced the form capistrata, the second split in the 
course of time into the forms picata and opistholeuca. 

The second option supposes the complex to have emerged through 2 
successive invasions into its present range from the range of ancestral taxa 
generally believed to be African, Middle Eastern and southwest Asian 
wheatears of the superspecies lugens — lugentoides — lugubris (see e.g. 
Panov 1989, Tye 1989). Moreover, the immigrants in one case may have 
come from the range of lugens, males of which have the same type of 
plumage pattern as capistrata males and comparatively large measure- 
ments. Another wave of colonists may have originated from the range of 
the lugubris group, males of which characteristically have a high degree of 
pigmentation, which is also a typical feature of the forms picata and 
opistholeuca (Tye 1989: 173). 

In order to discover which of the proposed scenarios is closest to the 
truth, there is a need for further comparative investigations within the 
'Eastern Pied Wheatear' complex, and also for a comparison of the vari- 
ous representatives of this group with the still little-known wheatears 
of the lugens — lugentoides — lugubris complex. It is recommended that 
priority in such future studies be given to approaches which focus on 
comparative ethology and molecular genetics. 


I am very grateful to Michael G. Wilson, who kindly translated the manuscript into English 
and Euan Dunn, who made valuable comments, both working at the Edward Grey Institute, 


Bel'skaya, G. S. 1961. On the ecology of the Eastern Pied Wheatear. Trudy Inst. Zool. 

Parasitol. Akad. Nauk Turkmen. SSR 7: 43-54 (in Russian). 
Desfayes, M. & Praz, J. C. 1978. Notes on habitat and distribution of montane birds in 

southern Iran. Bonn Zool. Beitr. 29: 18-37. 
Haffer J. 1977. Secondary zones of birds in northern Iran. Bonn. Zool. Monogr. 10. 
Kostina, G. N. & Panov, E. N. 1 981 . Individual and geographical variation in the song of the 

Eastern Pied Wheatear Oenanthe picata. Zool. Zh. 60: 1374-85 (in Russian). 
Loskot, V. M. 1972. Intraspecific variation and systematics of the Eastern Pied Wheatear 

Oenanthe picata (Blyth). Vestnik Zool. (4): 28-34 (in Russian). 
Lyubushchenko, S. Yu. & Grabovskiy, V. I. (in press). Phenotypic composition of Eastern 

Pied Wheatear {Oenanthe picata capistrata and O. p. opistholeuca) in their contact zone 

in southern Tadzhikistan (in Russian). 
Mayr, E. & Stresemann, E. 1950. Polymorphism in the chat genus Oenanthe. Evolution 4: 

Paludan, K. 1959. On the birds of Afghanistan. Vidensk. Medd. Dansk Naturh. Foren. 122. 
Panov, E. N. 1989. Hybridization and Ethological Isolation in Birds. Moscow (in Russian). 
Panov, E. N., Grabovskiy, V. I. & Lyubushchenko, S. Yu. (in press). Divergence and 

hybridogenous polymorphism in the 'Eastern Pied Wheatear' complex. Zool. Zh. (in 

Panow, E. N. 1974. Die Steinschmdtzer der nordlichen Palaarktis. Wittenberg Lutherstadt. 
Panow, E. N. 1980. Divergenz und Hybridisation in der Gruppe der Elstersteinschmatzer 

(Oenanthe picata). Mitt. Zool. Mus. Berlin. 56 Suppl. Ann. Orn. 4: 3-23. 
Stepanyan, L. S. 1978. Species Composition and Distribution of Birds in the USSR Fauna. 

Passeriformes. Moscow (in Russian). 
Ticehurst, C. B. 1922. Notes on some Indian Wheatears. Ibis (\\)4: 151-8. 
Tye, A. 1989. Superspecies in the genus Oenanthe (Aves, Turdidae). Bonn. Zool. Beitr. 40: 


Bull. B.O.C. 1 1 2A 249 Oenanthe picata complex 

Zarudnyi, N. A. 1923. On some chats {Saxicola picata Blyth, S. capistrata Gould, S. 
opistholeuca Strickl, and S. opistholeuca evreinowi Tj&v.). Izv. Turkestan. Otd. Russk. 
Geogr. Obshch. (Tashkent) 16: 72-81 (in Russian). 

Address: Dr E. N. Panov, A. N. Severtsov Institute of Evolutionary Animal Morphology 
and Ecology, Russian Academy of Sciences, Lenin Avenue 33, Moscow 117071, 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 251 R.L. Potapov 

Systematic position and taxonomic level of 
grouse in the order Galliformes 

by R. L. Potapov 

Received 26 May 1992 

The clear division of the Galliformes (gallinaceous birds) into two 
groups — the ancient Cracoidea (Cracids and Megapodes) and the 
younger Phasianoidea — was established when the very first morpho- 
logical revisions were made and, with rare exceptions (Clark 1960, 1964), 
has remained undisputed to the present day. The taxonomic status of 
these 2 groups varies from superfamily to suborder in the classifications 
proposed by different authors. Dividing the first group (Cracoidea) 
into the families Cracidae and Megapodiidae was an obvious course, as 
these differ morphologically and have long been widely separated geogra- 
phically. The second group (Phasianoidea) differs clearly from the first 
(Cracoidea) in the position of the hallux on the tarsus, but its taxonomic 
subdivision is generally rather complex and much less straightforward. 
Up to the present day, various authors have argued with varying degrees 
of conviction for the inclusion in the Phasianoidea of the following 
groups: turkeys, guineafowl, peafowl, pheasants, Old World quails, New 
World quails and grouse. During the last 2 centuries, all possible combi- 
nations seem to have been tried in order to classify these groups, which 
have been variously given the rank of subfamilies within the single family 
Phasianidae, treated as separate families, or some united within the 
Phasianidae, others treated as independent families. However, the most 
usual classification has been that which treated as separate families the 
Phasianidae (comprising the subfamilies Odontophorinae, Perdicinae, 
Phasianinae, Numidinae), Meleagridae and Tetraonidae. New evidence 
has, however, now been produced which suggests that the guineafowl 
should be elevated to family rank (Sibley & Ahlquist 1990, Sych 1990). 

The diversity of opinion with respect to classification of the 
Phasianoidea points above all to the low degree of divergence within 
the superfamily. It may further reflect the universal nature of phasianid 
morphology, which permits adaptation to a variety of environmental 
conditions. For example, the New World quails, despite having been 
separated longest from the main branch of phasianids (Sibley & Ahlquist 
1990), have developed so few distinctions from the latter that they have 
been almost invariably treated by morphologists as only a subfamily 
within the Phasianidae. This case indicates that the quite considerable 
differences in DNA between the New World quails and other phasianids 
(more so than between guineafowl and other phasianids) are barely 
reflected in their morphology. 

We have at least 2 methods for calculating the time of isolation of New 
World quails. One involves the use of starch gel electrophoresis with the 
fossil representatives of this group from the mid-Miocene in order to 
calibrate genetic distances (Gutierrez et al. 1983). Another method 
focuses on geological and palaeogeographical data from roughly the time 

R.L. Potapov 


Bull.B.O.C. 112A 

Figure 1 . Horny appendages on toes of grouse. A = cross-section through terminal 
phalange of Capercaillie (Tetrao urogallus). 1 = lateral scutes; 2 = first row of appendages; 
3 = second row of appendages; 4 = intermediate protuberance; 5 = foot papillae. B = 
transverse cross-section of growing appendage at its base; 6 = pulp. C: 7 = transverse 
cross-section of horny appendage; 8 = longitudinal cross-section of horny appendages. 
D = position of appendages when toe is in contact with branch. E = position of appendages 
when toe is in contact with snow. (From Potapov 1985.) 

of the disjunction of North America and Europe. Interestingly, both 
methods give the same result: isolation in the lower Oligocene, 
c. 35 million years ago. 

Based solely on DNA-hybridization data, Sibley & Ahlquist (1990) 
gave the New World quails the rank of family, the grouse that of sub- 
family. On the contrary, the grouse (which, like the turkeys, undoubtedly 
diverged much more recently than the New World quails — Sibley & 
Ahlquist 1990) show distinct morphological, ecological, ethological and, 
probably, also physiological differences, and we need to discuss the main 
features of this group separately. 

Morphological characteristics of grouse 

Pectinated toes 

First we should consider a feature which is common to all grouse 
(with one exception) and not found in any other birds. This is the horny 
appendages (pectination) along the sides of the toes (Fig. 1). These 
appendages are shaped like miniature elongated scoops or nails with blunt 
tips. Forming a single or double row on both sides of the toes, they break 
and fall off in spring and regrow each autumn before the onset of winter. 
Only in the willow grouse and ptarmigan (genus Lagopus) which live in 
the most severe climatic conditions are these appendages replaced by 

Bull. B.O.C. 112A 253 Systematic position of grouse 

thick feathering; the pectination is found, nevertheless, in rudimentary 
form in one member of the genus Lapogus, the White-tailed Ptarmigan 
L. leucurus (in addition it has many relict features), thus giving a clear 
indication that the feathering of the toes is a secondary development, 
evolving in place of the appendages. The functional significance of the 
appendages, which appear only for the winter, is obvious: they more 
than double the surface area of the foot, which is an important aid not so 
much to locomotion on such a friable surface as snow (in most cases such 
walking on the snow is not necessary) as to the need to burrow into the 
snow 1-3 times per day to escape the severe winter cold. Each horny 
appendage acts as a miniature scoop, thereby significantly increasing the 
digging function of the foot and enabling any grouse to dig itself into the 
snow within a matter of seconds. Snow-burrows serve as thermal refuges 
where birds may spend most of the day during hard frost and where the 
temperature is constantly around — 2 to — 3 °C regardless of the ambient 
temperature. The very fact that lateral pectination of the toes is not found 
in any other avian taxon significantly increases the taxonomic value of this 
feature. Similar structures are found in some desert lizards inhabiting 
loose sand (e.g. Phrynocephalus, Eremias) (Buxton 1928), but these are not 
homologues of grouse pectination, but rather transformed scales. 

Feathering of nostrils and toes 

Another characteristic feature of grouse is the full and thick feathering 
of the nostrils and, perhaps as a consequence, the complete absence of the 
horny covering flap, the operculum; in some members of the Phasianidae 
(e.g. Lerwa lerwa, Tragopan, Lophophorus, Tetraogallus) there is some 
feathering around and on the surface of the operculum, but the operculum 
itself is not reduced. 

In most grouse the tarsi are thickly feathered apart from a narrow strip 
along the rear side. The great majority also have lateral feathering 
extended to the base of the toes; in Lagopus, the toes are completely 
feathered, except for the upper part of the extreme tips. Many phasianids, 
especially northern or mountain species, have feathering on the upper 
part of the tarsus, but never extended to the lower third, still less to the 


Among special features of the skeleton, the most notable is the great 
width of the pelvis — -more than 75% of its length (in phasianids, the 
maximum width is up to 75.8%), while its depth is only 16-17% of its 
length (as against 25-30% in phasianids). Such a sharp increase in pelvic 
width has resulted in a characteristic bend in the femur which in turn 
brings about a shift in the centre of gravity to place it above the foot when 


There are no qualitative distinctions between the groups being com- 
pared, all are of a quantitative nature. The sole significant distinction — 
the absence in the grouse of the M. adductor digiti II (Hudson et al. 1959) 
has now lost its validity since the discovery that this muscle is lacking also 

R.L.Potapov 254 Bull. B.O.C. 1 12 A 

in a phasianid, namely the Tibetan Snowcock (Tetraogallus tibetanus) 

Digestive system 

One of the main features of the digestive system is the exceptionally 
strong development of the caeca in all grouse species, this being most 
pronounced in members of the genus Lagopus. The length of grouse caeca 
is directly correlated with the length of the winter season and its relative 
severity, even within different populations of a single species. Generally, 
the length of the 2 caeca in grouse varies from c. 60 to 139% of the length 
of the small and large intestine; in phasianids, this ratio is usually up to 
50%, in a few extreme cases up to 64% (Potapov 1985). 

Among other peculiarities of the digestive system we should mention 
the absence in grouse of the gall bladder, which is so characteristic of 
other members of the Galliformes. 

Ecological characteristics 

Most important in this context as the main distinction from the 
phasianids is the peculiar food and feeding behaviour of grouse — their 
unique ability to survive on a monotonous plant diet throughout the 
severe winter season. Food items include twigs, buds, catkins and needles 
of various deciduous and coniferous trees and shrubs (e.g. Betula, Alnus, 
Salix, Populus, Picea, Pinus, Abies), i.e. a diet rich in cellulose and low in 
proteins and fats. However, food of this type is so abundant in northern 
forests that the birds need not spend much time or effort to obtain the 
required daily amount. 

There are no fundamental differences between grouse and phasianids 
in respect of breeding strategy and timing (phenology), sex ratios, 
population dynamics, etc. The same general habitat types (open, bushy, 
forest, montane, etc.) are used by both groups, though grouse typically 
show a close link with forest and scrub vegetation and males of some 
species perform well-developed communal displays ('leks'). Open 
habitats invaded by grouse are primarily tundra (where some woody 
vegetation, even dwarf shrubs, is present), also to some extent steppe and 
semidesert, but never true desert. Grouse are found in all types of boreal 
forest, but have not penetrated into subtropical, still less tropical forests, 
the main reason being that their breeding range is confined within an area 
where there is a seasonal climate, with a pronounced winter period (snow 
cover, negative temperatures, short days). 

Behavioural characteristics 

The most remarkable feature of grouse behaviour is their ability 
to build snow-burrows as thermal refuges. For nocturnal or diurnal 
roosting, a bird uses vigorous movements of its bill and feet to dig a 
tunnel from 0.6 to 4 m long, at the end of which it makes a roosting 
chamber large enough to accommodate the bird comfortably, even with 
its feathers ruffled (Fig. 2). The depth of the chamber allows the grouse to 
stretch up and poke its head through the snow and look around before 
leaving its roost-hole. At moderate negative temperatures (minus 5 °C to 
minus 9 °C), grouse spend all the winter night in their burrows (Fig. 3), 

Bull.B.O.C. 112A 

,rrn ii>l ^ i ^n,nni)U))irr mm nn»unn)>nm 

Systematic position of grouse 



•• ^$f™*s 

x V 


Figure 2. Snow-burrow of grouse. A = vertical cross-section of chamber; 1= tunnel 
blocked with snow; 2 = platform of slightly thawed and compacted snow; 3 = solid faeces; 
4 = signs of snow being eaten by bird; 5 = future exit hole. B = position of bird in burrow. 
C = various types of tunnels. D = transverse cross-section of burrow (black indicates icing of 
walls, shaded area shows platform of slightly thawed and compacted snow). E = position of 
burrow at varying snow depths. (From Potapov 1985). 

and if the temperature is lower, all night and most of the day as well. In 
exceptionally low temperatures, a grouse can spend up to 22 hours per day 
or even more than 2 days in succession in its snow-burrow roost. 

Functional significance of the above-mentioned peculiarities 

All the characteristic features of grouse described above are directly or 
indirectly related to survival in the northern winter season and represent 
a highly effective complex of adaptations which allow the birds to be 
year-round residents, with no recourse to migration. This complex of 
adaptations is based on the ability to survive the winter on plant food of 
low nutritional value, but available in abundance and at low cost in both 
time and energy. In its turn, this ability is based on the presence of 
well-developed caeca into which passes all the liquid digestive extract 
(chyme) containing the main nutritionally valuable substances (fat, 
protein, micro-elements), also some less useful, even poisonous, sub- 
stances, extracted from buds, twigs, needles, etc. during the grinding 
process in the gizzard and their passage through the digestive tract. In the 
caeca, the extract undergoes treatment for not less than 24 hours (usually 
nearer 48 hours per portion), thus significantly prolonging the digestive 
process; otherwise, the passage of food through the alimentary canal 
without this delay in the caeca takes c. 4 hours. The chemistry of the 

R. L. Potapor 



-50 -HO -30 -ZO -10 C 

Figure 3. Time (Y-axis) spent outside the snow-burrow plotted against ambient 
temperature (X-axis). (From Potapov 1985.) 

digestive process in the caeca requires further research; nevertheless, 
the caeca have been found to have intensive secretory activity with an 
exceptionally well-developed absorbent surface of their epithelium, the 
area and efficiency of which are considerably increased by the existence of 
well-developed ridges extending along the caeca. The caeca are thus a 
special kind of reactor working uninterruptedly throughout the winter to 
provide the bird with a constant supply of energy and nutrients. 

It is on this main adaptation that all the other characteristic adaptations 
of tetraonid birds are based. They are able to survive on a diet of twigs, 
buds, catkins and conifer needles, i.e. items which are abundant and easy 
to obtain so that a minimum of time (30-90 minutes) needs to be devoted 
to gathering the daily ration. They have the ability to create thermal 
refuges under the snow which allow birds to regulate the ambient tem- 
perature by varying the time they spend in the burrow, which depends on 
the temperature outside. As a rule, the temperature in snow-burrows 
stays within optimal limits, just below °C, and can even be regulated by 
the bird: if the temperature in the burrow rises above °C and there is a 
consequent danger of the snow melting and the bird's plumage becoming 
wet, the grouse makes a small ventilation hole in the roof and the tempera- 
ture in the burrow quickly drops. The thick feathering around the nostrils 
condenses moisture from the air exhaled by the bird, thus preventing 
the walls of the chamber icing up and an oxygen shortage arising. Any 
moisture is extracted from the faeces during their passage through the 

Bull. B.O.C. 112A 257 Systematic position of grouse 

large intestine so that they are solid and dry when excreted and add some 
warmth to the air in the snow-burrow, while also to some extent absorb- 
ing unwanted moisture and thus helping to counteract the danger of icing. 
The bird's thick tarsal feathering is a superb thermo-isolating mechan- 
ism, giving a protective mattress against the cold floor. The harder the 
frost, the drier the snow and the better its insulating quality. If a thaw sets 
in, the snow becomes wet and unsuitable for roosting, but the grouse 
anyway no longer has a need for such a refuge once the temperature is °C 
or above. In general, staying in a burrow during low temperatures leads to 
a great saving in energy thanks to a sharp reduction in energy expenditure 
on thermoregulation (the lower limit of the thermoneutral zone for 
tetraonid birds is close to °C) and the virtually complete absence of 
locomotion. The decrease in energy expediture for thermoregulation 
alone, even in a moderate frost of — 20 °C, means that a grouse uses 
20—35% less of the energy required to survive at the given temperature 
otherwise than in a snow-burrow. It is not surprising, therefore, that the 
strategically important adaptation of making snow-holes has led to the 
evolution of certain morphological features which so sharply distinguish 
grouse from the other Galliformes: pectinated toes, which greatly 
increase the digging ability of the feet when burrowing into snow; 
thick feathering around the nostrils which protects them from snow and 
reduces moisture produced by condensation of the exhaled breath; and 
thick tarsal feathering (extending to the toes in some species) which 
acts as an insulating layer between the bird's body and the floor of the 


The above descriptions present a general picture of how the whole 
complex of adaptations peculiar to grouse operates. These adaptations 
function only during the winter and enable birds to lead a sedentary life 
despite the marked seasonality of the climate. Gallinaceous birds have, 
through representatives of the grouse, colonized a completely new natural 
zone which came into being and evolved during the last geological epoch 
(the Pleistocene). This is the zone dominated by the boreal tree-shrub 
vegetation-type (both deciduous and coniferous), which is in turn well 
adapted to sharp seasonal changes in climate. The enormous area occu- 
pied by this zone embraces practically all the land surface of the Northern 
Hemisphere north of latitude 40 °N. In other words, the grouse occupy at 
least 40% of the whole range occupied by gallinaceous birds. For the 
relatively ancient Galliformes (Eocene epoch), the whole of the boreal 
zone was completely new, as the order had evolved in the tropics and 
subtropics and only a few representatives of families other than grouse 
eventually managed to pentrate into the southern margins of the boreal 
forest zone. In this connection, we should bear in mind the generally 
accepted principle that the wider the new adaptive zone, the higher the 
taxonomic rank of a group by the time it occupies the greatest part of 
the zone in question (Simpson 1969). All these reasons should encourage 
us to regard the grouse as a separate family within the suborder 

R. L. Potapor 258 Bull. B.O.C. 1 12A 

All large taxa within this suborder (pheasants, partridges, New and Old 
World quails, peafowl, guineafowl, turkeys and grouse) differ one from 
another to varying degrees in a number of mainly morphological features 
and this doubtless reflects the complex structure of the suborder and 
varying speed of evolutionary processes. Qualitatively and quantitatively 
the most distinctive groups are the grouse and guineafowl. However, 
while the grouse have predominantly new evolutionary features, the 
guineafowl are a distinctly archaic group. It is quite possible that the 
guineafowl also merit separation as an independent, but extremely 
primitive family, approaching in a number of morphological features, the 
suborder Cracoidea (Sych 1990). 

Deserving of special attention are the New World quails whose mor- 
phology has not allowed taxonomic rank higher than subfamily within the 
Phasianidae. However, DNA-hybridization data have demonstrated that 
this group separated from the main branch of phasianids 35-65 million 
years ago, and should therefore be given family rank (Sibley & Ahlquist 
1 990, Sibley & Monroe 1 990). It should be noted, incidentally, that deter- 
mining the time when the New World quails diverged from the other 
phasianids can be done without recourse to the DNA-hybridization 
method, but instead by using palaeogeographical data from the time 
when the European and American continents separated. The DNA- 
hybridization results merely show the divergence of the chromosome 
structures; but in the present case it is clear that there is no corresponding 
divergence in the morphology of the groups being compared. This kind of 
dichotomy is by no means rare, having arisen regularly in recent times. In 
the case under investigation, it is my firm conviction that preference 
should be given to a judgement based on morphological criteria as these 
most convincingly show the results of the process of evolution. In assess- 
ing the taxonomic level of grouse, we therefore give higher priority to 
morphological features, their adaptive (functional) significance and 
specificity of ecological niches. On this basis, the relatively young, 
but morphologically and ecologically distinct grouse undoubtedly merit 
family rank within a superorder Phasiani, while the much older New 
World quails, which show no significant distinctions from the partridge 
and quails of the Old World (despite having separated millions of years 
ago), should be treated as a subfamily within the Phasianidae. The 
guineafowl, which are also younger than the New World quails, but 
(unlike grouse) are distinguished by their predominantly archaic features, 
suggesting a close relationship with the suborder Cracoidea, should 
evidently also be given family rank (Sych 1990). 

The results of the process of evolution are not dependent simply on 
time, nor is taxonomic rank a mere function of time; it can be determined 
only after a detailed and comprehensive investigation of morphological, 
ecological and ethological features. 


I am grateful to Michael G. Wilson (Edward Grey Institute, Oxford) for improving the 
language of the paper and also to M. & E. Potapov for typing the manuscript. 


Buxton, P. A. 1928. Animal Life in Deserts. London. 

Bull. B.O.C. 112A 259 Systematic position of grouse 

Clark, G. A. Jr. 1960. Notes on the embryology and evolution of the Megapodes (Aves: 

Galliformes). Postilla 45. 
— 1964. Ontogeny and evolution of the Megapodes (Aves: Galliformes). Postilla 78. 
Gutierrez, R. J., Zink, R. M. & Edwards, G. D. 1983. Genetic variation, systematic, and 

biogeographic relationships of some galliform birds. Auk 100: 33—47. 
Hudson, G. E., Lanzillotti, P. J. & Edwards, G. D. 1959. Muscles of the pelvic limb in 

galliform birds. Amer. Midi. Nat. 61: 1-67. 
Morioka, H. 1975. Toe extensors and flexors of Tibetan Snowcock. Bui. Natn. Sci. Mus. 

Ser.A. (Zool) 1(2): 123-135. 
Potapov, R. L. 1985. Fauna of the USSR N.S. No. 133, Birds 3(1). Order Galliformes, 

Part 2 Family Tetraonidae. Leningrad. (Russian). 
Sibley, C. G. & Ahlquist, J. E. 1990. Phylogeny and Classification of Birds. New Haven, 

Sibley, C. G. & Monroe, B. L. Jr. 1990. Distribution and Taxonomy of Birds of the World. 

New Haven, Connecticut. 
Simpson, G. G. 1969. The Major Features of Evolution. New York. 
Sych, V. F. 1990. Morphology of the Locomotory Apparatus of Galliform Birds. Doct. Thesis, 

Kazan' University. 

Address: Prof. Roald L. Potapov, Zoological Institute, Russian Academy of Sciences, 
Universitetskaya nab. 1, St Petersburg 199034, Russia. 

© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 261 K. H. Voous 

Reflections on the genus in ornithology 
by Karel H. Voous 

Received 20 March 1 992 

In the biologist's every day life, the use of a genus name is inevitable if 
not compulsory. Whether he studies the protozoan Entamoeba, the 
mosquitoes Culex or Anopheles, the herring Clupea, the Great Tit 
Parus or man himself Homo, for him the genus-name is significant if not 
decisive. He rarely ponders on what a genus actually means as a concept in 
systematic biology. Indeed, in most instances this is of no relevance to 
him. However, he may suddenly become painfully aware of it when 
taxonomists start to arrange the species of his study according to revised 
ideas of generic grouping. Worse still, he may see the familiar 
genus-name changed. 

Almost 30 years ago I tried to formulate my thoughts on the essence of 
the genus in a Dutch journal (Voous 1964). Some time later I explained 
these in another paper written in English (Voous 1975), adding 
remarks on the theoretical and practical limits of genera in the warblers 
Acrocephalus and Hippolais, the gulls Larus and terns Sterna, and the 
geese Anser and Branta. The main conclusions were that, in contrast to 
species, genera have no reality in nature, that genera should be defined 
pragmatically and that non-taxonomic biologists are primarily interested 
in genus-names rather than in the genus itself. Mutatis mutandis this 
would apply to all other systematic categories above the species level. 
Only at the higher end, towards the category of the phylum, diversity in 
ontogeny and structure shows differences in principle rather than degree. 

Introductory considerations 

Renewed interest in the genus was induced by the publication of 2 
important ornithological works, both of which have made important and 
markedly bold attempts to group the species of the birds of the world 
according to modern views and methods: Hans E. Wolters (f 1991), Die 
Vogelarten der Erde (1975-1982), and Charles G. Sibley & B.L. Monroe, 
Jr., Distribution and Taxonomy of Birds of the World (1990). 

Wolters announced himself as a strict follower of W. Hennig's phylo- 
genetic systematics (Hennig 1950, 1966). Sibley & Monroe, though also 
following Hennig's principles of cladistic analysis, constructed a gigantic 
new building of bird systematics, based on the corner stones of DNA- 
studies. As was to be expected, Wolters's and Sibley & Monroe's classifi- 
cations are as different inter se as each of these is from the traditional 
Wetmore system and its modifications. 

Though of little relevance here, I have always had my own serious 
doubts as to the significance of Hennigian methods in taxonomy (Voous 
1980, concurred with by Mayr 1982; 226-233). Whether viewed as a 
branching tree up to the finest twigs and end buds, or as a pruned bunch of 
grapes in which the pruning is executed by all natural phenomena in 
existence, the growth of certain twigs or grapes are favoured, while others 

K. H. Voous 262 Bull. B.O.C. 1 12A 

lead to extinction or radical pruning. The result is that the tree of life 
formed by both transient and recent species is far too complicated and too 
incompletely known, if known at all, so that the recognition of branching 
points, as required by Hennig, involves too many basic uncertainties as to 
be of any real help in understanding the road of evolution. When making 
a choice out of a multitude of possible options for the reconstruction 
of a phylogenetic tree, the word "parsimonious" emerges as of having 
magical power. I must confess that, English not being my mother's 
tongue, I have met this word only in Hennigian contexts and I am not 
impressed by it. As every experienced biologist knows, nature's ways are, 
and probably always have been, more capricious and unpredictable than 
man can encompass. Hence, all Hennigian-derived phylogenetic trees 
are theories, not necessarily better or nearer to reality than any other 
serious endeavour to reconstruct the past. Trying to discriminate 
between 'apomorphic', 'plesiomorphic' and other categories of charac- 
ters, which is another important item in Hennigian methodology, is as 
subjective a procedure as it was to distinguish between homologous 
and analogous characters or structures in old-fashioned comparative 
anatomy, which therefore ultimately failed. 

With this in mind and passing by the several published theoretical 
observations on the genus concept, I have ventured to evaluate the use of 
genera in the comprehensive works of Wolters (1975-1982) and Sibley & 
Monroe (1990). The results of the evaluation will be compared with the 
conclusions arrived at in earlier papers (Voous 1964, 1975). 

Comparing the uses made of genera in avifaunal lists 

In order to evaluate the genus concepts adhered to by Wolters (1975— 
1982) and Sibley & Monroe (1990) I have compared the genus-names 
accepted in these works with those used in: 

(1) New World breeding birds, as in the A.O.U. Check-list of North 
American Birds (6th ed., 1983): Nearctic region only. 

(2) Old World breeding birds, as in the List of Recent Holarctic Bird 
Species (Voous 1973, 1977): Europe only. 

(3) Tropical Asiatic birds, as in The Birds of Sumatra (van Marie & 
Voous 1988): breeding birds of Sumatra and satellite islands. 

As stated before, Wolters has tried to apply cladistic methods at every 
taxonomic level, including that of subgenera. Hence his classification 
differs from that of any of his predecessors. The actual reasoning behind 
each individual case is not explained, but the reader is referred to an 
earlier paper on the limits of genera in ornithology in general (Wolters 
1971). As a result Wolters lists no less than 356 (289) genera in North 
America, 270 (213) genera in Europe, and 281 (220) genera in Sumatra 
(traditional numbers added in parentheses). 

In contrast, Sibley & Monroe have been wise enough to lay the stress on 
their truly revolutionary arrangement and sequence of higher taxonomic 
categories, viz. tribe, family, infraorder, suborder, order, parvclass, 
infraclass, subclass. They have rarely deviated from the traditional path 
in the extent and limits of genera and the use of genus-names. This is all 
the more pleasurable since the names and their meaning in taxonomy will 

Bull.B.O.CAXlA 263 The genus in ornithology 

be recognised by ornithologists and biologsts of any discipline. Actually, 
their basically quantitative biochemical methods would have hardly left 
them room for deciding otherwise. Sibley & Monroe list 291 (289) genera 
in North America, 212 (213) genera in Europe, and 226 (220) genera in 
Sumatra (traditional numbers added in parentheses). 

Fortunately, Wolters and Sibley & Monroe concur in as many as 24 
instances, listed below, in which they deviate from one or more of the 
traditional classifications with which their works were compared: 

Morus (not Sulci) bassanus Rhaphidura (not Chaetura) 

Ixobrychus (not Dupetor) flavicollis Tachymarptis (not Apus) melba 
Nyctanassa (not Nycticorax) Todiramphus (not Halcyon) chloris 

Casmerodius (not Egretta) albus Actenoides (not Halcyon) concretus 

Mergellus (not Mergus) albellus Tricholestes (not Hypsipetes) 

Asturina (not Buteo) nitida Iole olivacea (not Hypsipetes 

Porphyrio (not Porphyrula) Ixos (not Hypsipetes) malaccensis 

Burhinus (not Esacus) magnirostris Hemixos (not Hypsipetes) flavala 
Eudromias (not Charadrius) Eumyias (not Muscicapa) 

morinellus thalassima 

Micropalama (not Calidris) Eumyias (not Muscicapa) indigo 

Steganopus (not Phalaropus) Psilorhinus (not Cyanocorax) morio 

Larus (not Xema) sabini Hesperiphona (not Coccothraustes) 


Case studies 

Anatidae: swans, geese, ducks 

The number of genera recognized by Wolters is 72, by Sibley & Monroe 
44, average number of species per genus 2 and 4, respectively. Recognis- 
ing 13 genera of surface-feeding or dabbling or paddling ducks by 
Wolters, instead of the one genus Anas by Sibley & Monroe, means in 
terms of cladistic analysis that Wolters's first genus, "Melananas" for the 
African Black Duck Anas sparsa, is the 'sister-group' of all following 
genera combined. It is hard to believe that evidence in favour of this 
suggestion is available, nor that the 3 species of wigeon 'Mareca\ 
following 'Melananas* have subsequently together branched off from the 
main and only stem from which in later times all other Anas-ducks have 
derived. The scholarly ecological studies by Johnsgard (1965) on which 
Voous (1973) and others have based their sequence of ducks, would not 
suffice for that purpose, as nothing is known of the real history of the 
evolution of these ducks. 

Curiously enough, the delimitation of these duck-genera by Wolters 
conforms almost exactly with the genera recognised in older European 
works and perpetuated still in the 4th edition of the A.O.U. Check-list 

K.H.Voous 264 Bull. B.O.C. 11 2A 

of North- American Birds (1931) in which Anas is split into 9 genera: 
Anas, Chaulelasmus, Dafila, Paecilonetta, Eunetta, Nettion, Querquedula, 
Mareca and Spatula. Morphological differences (e.g. in the structure 
of the bill, corresponding with feeding habits and habitats) formed the 
background for recognising these groups as genera. So we are back to 
where taxonomy started: comparative morphology, as a subjective, but 
verifiable basis for genus-recognition, now in modern Hennigian dis- 
guise. Realising that this is the position of a modern classification does not 
mean yielding to scientific incapacity, but is merely to put the record 

Using 50 (Wolters) or 35 (Sibley & Monroe) genera for all 40-42 duck 
species together, signifies differences in taxonomic view and treatment, 
but one method is scientifically not more acceptable than the other. For 
the general ornithologist, however, a restricted number of genus-names 
reflects the situation more clearly that the similarity of duck species in 
appearance and behaviour is more apparent than the difference. Besides, 
in spite of differences in male breeding attire, these birds are genetically 
remarkably closely related as testified by the occurrence of the most 
extravagant, and often fertile, hybrid combinations, occurring as well in 
captivity as in nature; and was it not the possibility of producing fertile 
hybrids that was considered the crucial condition for recognising ''wide" 
genera in Wolters's earlier writings (Wolters 1949, 1950)? 

Falconidae : falcons 

The number of genera of falcons recognised by Wolters is 1 0, by Sibley & 
Monroe one, average number of species per genus 4 and 39, respectively. 
Admittedly, there are marked differences between the 'inoffensive' 
kestrels ' Tinnunculus 1 and the 'fierce' gyrfalcons and peregrines 
' Hierofalco' . If the use of the one genus-name Falco for all falcons is 
considered unsatisfactory because of the differences between the 
extremes, the splitting up of the genus could be considered a remedy. 
This would leave Merlin ' Aesalori ', Hobby 'Falco' and Eleonora's 
Falcon 'Falco' in intermediate positions and would place the Red-footed 
Falcon 'Erythropus' on a specialised side-branch. Still, the history of the 
evolution of falcons is virtually unknown. For the use of a variety of 
genus-names for the falcons, nothing but the old-fashioned method of 
weighted phenological taxonomy remains in stock. Trying to find 'sister- 
groups' in this and comparable cases is unrealistic, and Hennigian 
methods fail or are at best as subjective as any other method. 

Calidridinae (Eroliinae): sandpipers 

The number of genera recognised by Wolters is 1 1 , by Sibley & Monroe 
6, average number of species per genus 2 and 4, respectively. Basically the 
same considerations as in the case of the Anas-ducks could apply to the 
use of genus-names in this group of waders which, as in ducks, look so 
much alike and behave so similarly inter se, yet in some respects can be so 
markedly different. Subjective comparative morphology rather than the 
reconstruction of branching points in their long line of evolution has 
provided the basis for the recognition of the genera Calidris (Knot), 
Erolia (Curlew Sandpiper), Heteropygia (Pectoral Sandpiper), Ereunetes 

Bull. B.O.C. 112A 265 The genus in ornithology 

(Semipalmated Sandpiper), Crocethia (Sanderling), Pelidna (Dunlin), 
Arquatella (Purple Sandpiper). They are distinguishable mainly on 
account of one or two vestigial webs at the base of toes and the absence, 
presence or size of the hind toe, none of which characters seem to play a 
major specific role in sandpipers' lives. Apart from weak scientific evi- 
dence, a profusion of genus-names more likely conceals than elucidates 
the degrees of relationship in these waders. 

Laridae : gulls 

The number of genera of gulls recognised by Wolters is 12, by Sibley 6, 
average number of species per genus 4 and 8, respectively. In a former 
paper (Voous 1975) I have tried to show that a wide genus Larus, includ- 
ing such extremes as the Great Black-backed Gull Larus marinus and 
Little Gull Larus minutus is consistent with the facts only when in the 
related terns a similarly wide genus concept is accepted. It was therefore 
proposed to list the Caspian Tern (caspia) and the Little Tern (albifrons) 
and all terns in between as members of one genus Sterna. The alternative 
view is to have these 2 genera divided into several, which is what Wolters 
has done. Apart from the Kittiwake Rissa and the Ivory Gull Pagophila, 
all 'white-headed' gulls, from Common Gull (canus) to Great Black- 
backed (marinus) and Glaucous (hyperboreus) Gulls are listed by Wolters 
as Larus, as opposed to the "hooded' gulls, which are arranged in as many 
as 7 genera: Adelarus (Hemprich's or Aden Gull, 2 species), Ichthyaetus 
(Great Black-headed Gull, 1 species), Chroicocephalus (Black-headed 
Gull, 13 species), Atricilla (Laughing Gull, 3 species), Hydrocoelus 
(Little Gull, 1 species), Rhodostethia (Ross's Gull, 1 species) and Xema 
(Sabine's Gull, 2 species). Even a detailed cladistic background for this 
classification cannot provide the real evolutionary history which has 
brought about the present wealth of gull species, disclosing the subjective 
nature of this arrangement. Apart from that, the question remains 
whether one considers it more practical and helpful to adhere to one, well- 
defined large genus or alternatively should accept a number of less clearly 
defined smaller genera. Obviously, most present authors opt for the least 
amount of genus splitting. 

Concluding remarks 

The practicability and direct understanding of the limits of genera and of 
genus-names are the most relevant, and at the same time most widely 
appreciated, requirements for the genus, at least in ornithology. Most 
authors agree on the fact that whenever possible the genus should include 
a monophyletic group of species distinct from other such monophyletic 
groups. In most cases, in the absence of palaeontological data, the reality 
of a monophyletic origin of an individual genus cannot be or has not yet 
been proved. Hennigian analysis has not improved this situation. Real 
though the clustering of species is in evolutionary history, the reality and 
even the meaning of genus-limits are questionable. Genus-names remain 
as auxiliary help for understanding and memorising classification systems 
and in this respect are useful for any kind of ornithological research. 
Pragmatic rather than scientific values should be attached to bird genera 
and their naming. 

K. H. Voous 266 Bull. B.O.C. 112A 

In addition some of my earlier conclusions seem to have remained 
valid: ( 1 ) species, as functions of time and place, are a reality in nature; (2) 
genera are abstractions and as such do not exist in nature; (3) species can 
be discovered in nature, genera cannot; genera are invented (Voous 1964); 
(4) evolutionary development is gradual; in contrast, the distinction of 
genera is discontinuous by its very nature; (5) the recognition of genera 
should not be considered a necessary means of expressing evolutionary 
relationships, a presumption which after all is an unwelcome heritage of 
19th century thinking; (6) "The choice in the use of [named] genera 
should be practised according to the same standards as [for] literary style 
and with the same . . . elegance and precision, combining the subtilities of 
art with the [rigid] abilities of science" (Voous 1975: 982). 


American Ornithologists' Union. 1931. Check-list of North American Birds. 4th ed. 

American Ornithologists' Union. 1983 6th ed. Lawrence, Kansas: Allen Press. 
Hennig, W. 1950. Grundzuge einer Theorie der phylogenetischen Systematik. Berlin: 

Deutscher Zentralverlag. 

— 1966. Phylogenetic Systematics. Urbana, Illinois: Univ. Illinois Press. 
Johnsgard, P. A. 1965. Handbook of Waterfowl Behaviour. London: Constable. 

Marie, J. G. van & Voous, K. H., 1988. The Birds of Sumatra. British Ornithologists' Union 

Check-list No. 10. Zoological Museum, Tring, Herts, UK. 
Mayr, E. 1982. The Growth of Biological Thought. Cambridge, Mass. and London: Bellknap 

of Harvard Univ. Press. 
Sibley, C. G. & Monroe, B. L., Jr. 1990. Distribution and Taxonomy of Birds of the World. 

New Haven: Yale Univ. Press. 
Voous, K. H. 1964. Het genusbegrip in de zoologie in theorie en praktijk. Vakblad Biol. 44: 


— 1973. List of recent holarctic bird species. Non-Passerines. Ibis 115: 612-638. 

— 1975. An aberrant Reed Warbler, or: on the inequality of genera in birds. Ardeola 21: 


— 1977. List of recent holarctic bird species. Passerines. Ibis 119: 223-250, 376-406. 

— 1980. New developments in avian systematics: a summary of results. Acta XVII Congr. 

Int. Orn. Berlin (1978): 1232-1234. 
Wolters, H. E. 1949. Beitrdge zur Gattungssystematik der Vogel. Krefeld:: Goecke & Evers. 

— 1950. Beitrdge zur Gattungssystematik der Vogel. II. Krefeld: Goecke & Evers. 

— 1971. Probleme der Gattungsbegrenzung in der Ornithologie. Bonn. Zool. Beitr. 22: 


— 1975-1982. Die Vogelarten der Erde. Berlin: Parey. 

Address: Professor Dr. K. H. Voous, Maasdamlaan 28, 1272 EM Huizen, The Netherlands 
© British Ornithologists' Club 1992 

Bull. B.O.C. Centenary Suppl. 1992, 1 12A 267 F. Vuilleumier, M. LeCroy & E. Mayr 

New species of birds described 
from 1981 to 1990 

by Franfois Vuilleumier, Mary LeCroy & Ernst Mayr 

Received 28 May 1992 

At the VHIth International Ornithological Congress in Oxford, Meise 
(1934) presented a detailed review of avian taxa described as new in the 
1 5 year period from 1920 to 1934. No fewer than 600 new binomina were 
described in those 15 years. Meise (1934: 61) thought that "at least 135, 
at most 170-200 [of these 600 proposed species were] good species". 
This represents a rate of 40 new species names per year, and from 9—13 
'good' new species per year. Four years later, at the IXth International 
Ornithological Congress in Rouen, Meise (1938) presented "not only 
the species of birds described since July 1 934, but also most of the species 
described between 1920 and 1934, which had not been presented in 
London in 1934." He included 59 species names, 36 of which were 
described between 1920 and 1934. This left 23 new species described 
from 1935 to 1938, a rate of about 6 new species per year. Much less 
detailed than the 1 934 paper, the 1938 one simply listed the new names for 
the 1934-1938 period and the supplement for 1920-1934. The 1934 
paper included the new species in a systematic order and grouped them by 
major regions as well: North and South America; Africa, Madagascar 
and southern Arabia; Palaearctic Region; Indomalayan Region; Indo- 
australian Mixed Region; and Papuan Region and Polynesia. It gave 
a critical evaluation of the new names (Meise 1938), and placed them 
in a number of categories, including: "I. Recognized as a species"; 
"II. Recognized as subspecies"; "III: Homonym"; "IV. Synonym" 
(with several subcategories); and "V. Not recognized". By contrast, the 
1938 list (Meise 1938) only gave the species names grouped in geographic 
order. Meise (1938) indicated that the list "did not correspond to all 
described species" and that "several species must rather be considered as 
subspecies"; but no specific annotations were made. 

From the World War II years onward, the responsibility for periodic 
reviews of new avian species has been assumed by members of the scien- 
tific staff of the Department of Ornithology at the American Museum of 
Natural History (AMNH), most notably Ernst Mayr. Thus the 4-year 
period 1938-1941 (53 putative new species) was covered in the first 
AMNH review (Zimmer & Mayr 1943). The second (Mayr 1957) covered 
the 15-year period from 1941 to 1955 (74 putative new species), the third 
(Mayr 1971) the 10-year period from 1956 to 1965 (51 putative new 
species). The fourth instalment (Mayr & Vuilleumier 1983) reviewed 
critically the 48 species described as new in the 10 years between 1966 and 
1975, and the fifth instalment (Vuilleumier & Mayr 1987) discussed the 
18 species described as new in the 5-year period from 1976 to 1980, plus 
one species that had been omitted from the fourth report. 

The present article is therefore the sixth AMNH instalment. It covers 
the 43 new species of birds that have been described between 1981 and 

F. I 'uilleumier, M. Let Yoy & E. Mayr 268 Bull. B.O.C. 1 1 2A 

1990 (listed alphabetically in Appendix I), thus bringing the analysis up 
to date. The present report also reviews 3 species that had been over- 
looked in the compilation of previous reports (Appendix II), discusses 
2 taxa that have been described as potential new species in the period 
1981-1990 but that were not given binomina (Appendix III), and makes 
comments on 13 species discussed in previous reports, and for which 
information is very scanty (Appendix IV). As in the last instalment, 
species are grouped under 2 headings: Old World and New World. 
Within each region, the systematic order of families and subfamilies 
follows Morony et al. (1975). 

This review, as the earlier ones, provides ornithologists with a critical 
summary of information on bird species described as new in the litera- 
ture. After a study of the available evidence, each putative new species 
is ranked in one of several categories. To facilitate comparisons these 
categories are the same as in previous instalments in this series: 

Aa New species in new genera 

Ab New species not clearly members of a superspecies 

Ac Allospecies (members of a superspecies) 

Ba Species inquirendae 

Bb Subspecies 

Be Synonyms 

Bd Invalid names 

As in our earlier reports superspecies are indicated by brackets 
according to the procedures suggest by Amadon (1966). 

While preparing this review we have noticed that there is an unhealthy 
disease striking some ornithologists at present, aptly named "new-species 
fever" by Remsen (in litt). They seem impelled to describe as new a bird 
that seems to differ from a known species without collecting the data and 
making the careful studies that are necessary for an evaluation of relation- 
ships. General ornithological or natural history magazines (e.g. Ducks 
Unlimited, Animal Kingdom, Ornis, BBC Wildlife, World Birdwatch, 
American Birds, Der Falke, and others) and science journals (e.g. Nature) 
often carry popular articles about putative new species of birds, and 
recently a book (Stap 1990) recounted the search for novelties in 
the jungles of Amazonia. In several instances, putative new species 
have prematurely been incorporated into field guides (e.g. Diomedea 
amsterdamensis in Harrison 1985; Calidris paramelanotos in Hayman et al. 
1986). We have attempted, in this summary, to bring together this scat- 
tered literature of varying quality as well as material from the standard 
ornithological literature and present a coherent evaluation of each new 

In addition, we have become concerned at the careless way in which the 
descriptions of new species are sometimes presented. Evaluation is diffi- 
cult when descriptions are based on fragmentary data. Two of us (LeCroy 
& Vuilleumier 1990) presented a poster paper at the XXth International 
Ornithological Congress in New Zealand, making recommendations 
for criteria to be used in describing new species of birds. We have 
expanded these suggestions and publish them as a separate paper in this 

Bull. B.O.C. 1 12A 269 New species 1981-90 

We reiterate a request made earlier (Vuilleumier & Mayr 1987) and 
ask that ornithologists who describe new species send us copies of their 
papers, to facilitate our task in the future, and to ensure the continuity of 
this catalogue, which we believe has proven helpful to the ornithological 
community. General reviews making use of instalments in this series 
include Vuilleumier (1976) and Prigogine (1985). 

New taxa of subfossil birds (e.g. Dromaius baudinianus — Parker 1984 
and Ara cubensis — Wetherbee 1985) are not treated in this paper, which 
deals only with extant taxa. 



(1) Diomedea amsterdamensis Roux, Jouventin, Mougin, Stahl & 
Weimerskirch 1983, L'Oiseau et R. F. O. 53: 8— Plateau des 
Tourbieres, Amsterdam Island 37°50'S, 77°35'W, Indian Ocean. 
= Diomedea (exulans) amsterdamensis (Bb). 

The head and wing of a bird found dead on 28 March 1982, preserved in 
the Museum National d'Histoire Naturelle (MNHN) in Paris (C. G. 
1982—1139) form the holotype of this new species. No additional 
specimens were collected owing to the threatened status of this taxon. 
The authors did not find any specimen of large albatross from the 
Amsterdam Island population in the collections of the MNHN (other 
than the holotype), the Natural History Museum (BMNH) in London, 
the American Museum of Natural History (AMNH), the Carnegie 
Museum in Pittsburgh, the National Museum of New Zealand, or the 
U.S. National Museum (USNM) in Washington. 

Although the existence of a breeding population of a large albatross on 
Amsterdam Island has been known since 1951, very little was known 
about these birds until 1981, when 7 breeding pairs were found and 
their behaviour observed until the young fledged. The total population 
size, from data gathered in 1979, 1981 and 1982, is estimated at 30-50 
individuals. The distribution of this population at sea is entirely 

Diomedea amsterdamensis was described on the basis of field obser- 
vations and photographs of 23 breeding adults, and is illustrated with line 
drawings and black and white photographs. This population is closely 
related to D. exulans and D. epomophora. D amsterdamensis differs from 
D. exulans and D. epomophora in its much darker colouration, in the dark 
terminal patch at the tip of the bill, in its white eyelid, in its underwing 
pattern, and in the timing of its breeding cycle. Roux et al. (1983) con- 
cluded (translated from the French): "The originality and the absence 
of variability in the colour characters of plumage and bill testify to the 
reproductive isolation of this population. Moreover, the phenology of its 
breeding cycle forbids [interdit in the original] any hybridization with the 
other populations of D. exulans and D. epomophora." 

Bourne (1989: 110) reviewed the classification of the large albatrosses. 
He pointed out that D. amsterdamensis "appear[s] to be rather similar 
in size, proportions and appearance to the birds assigned to exulans from 

F. I uilleumier, M. LeCroy & E. Mayr 270 Bull. B.O.C. 1 12A 

the Antipodes Islands in the Pacific". The white eyelid, Bourne (1989: 
110) remarked, was thought to be "a variable character in Wandering 
Albatrosses" by Murphy (1936). Bourne (1989: 111-113) also warned 
of possible nomenclatural problems: "If it is accepted that Edwards' 
birds [from which Linnaeus described the species] probably came from 
Amsterdam Island, the well-known name exulans would take priority 
over amsterdamensis, while if it is accepted that this is a distinct species 
another name, chionoptera, would then have to be used for most of the 
other populations currently included in Diomedea exulans.'' Because 
of difficulties in determining the identity of the population described 
by Edwards, however, Bourne (1989) suggested that the Amsterdam 
Albatross be called Diomedea exulans amsterdamensis, an opinion we 
accept here, (Bb). In Bourne's (1989: 113) words, amsterdamensis is "a 
small pelagic form which retains the immature plumage into adult life". 
Sibley & Monroe (1990: 327) included exulans and amsterdamensis as 
allospecies in a superspecies. Some ornithologists (for instance Jouanin, 
pers. comm.) feel that exulans, epomophora and amsterdamensis are 3 
species in the same subgenus. Others (e.g. Boles, in litt.) point out that 
some populations of exulans approach amsterdamensis in colour. 

Jouventin et al. (1989) reviewed data on the breeding biology of the 
Amsterdam Island population of great albatross, and compared this 
population to others in the species epomophora and exulans. The size of the 
population at this later date was estimated to be about 65 birds (between 
a minimum of 52 and a maximum of 90). Lequette & Jouventin (1991) 
discussed behavioural similarities and differences among the different 
taxa of great albatrosses and described the displays of Diomedea 
amsterdamensis. They concluded that D. epomophora is "more distinct 
than the other two [species {exulans and amsterdamensis)] which never- 
theless present some differences in their nuptial displays" (Lequette & 
Jouventin 1991: 391). 

Given some of the uncertainties of classification of the great albatrosses 
(e.g. Bourne 1989, Lequette & Jouventin 1991), it is to be regretted that 
authors of field guides (e.g. Harrison 1 985) should have hurried to include 
amsterdamensis as a new species without having had the benefit of prior 
critical assessment. 


(2) Rallus okinawae Yamashina & Mano 1 981 , J. Yamashina Inst. Ornith. 

13: 2 — Woodland path near Mt. Fuenchiji, Kunigami-gun, Okinawa 

Prefecture, Japan. 
= Gallir alius [torquatus] okinawae (Ac). 

This new rail taxon, from the island of Okinawa, was not discovered 
until 1978. The holotype, an adult female, was found along the road- 
side on 2 June 1981, and is preserved in the Yamashina Institute for 
Ornithology (No. 810141). Two other birds, a juvenile captured 28 June 
1981, and an (unsexed) adult caught 4 July 1981, were photographed, 
banded, and released. They are illustrated in 3 colour plates (from photo- 
graphs) in Yamashina & Mano (1981). Rallus okinawae was compared to 
various taxa of the torquatus group {torquatus , kuehni, celebensis, limarius, 

Bull. B.O.C. 1 12A 271 New species 1981-90 

and sulcirostris), and found to have longer tarsi. This, coupled with the 
short and "soft" secondaries and tail feathers, suggested to Yamashina & 
Mano (1981) that okinawae has "very poor" flying ability, and hence that 
it is "a distinct new species". 

Brazil (1991: 111—112) summarizes what is now known of this bird. Its 
population, thought at first to be very small, is now believed to number 
between 1000 and 2000 birds. "It occurs in sub-tropical evergreen forests 
with dense undergrowth, but also along forest edges and in small forest 
patches, scrub and even agricultural land where it borders pools." 
The bird appears "almost, but not quite, completely flightless" (Brazil 
1991: 112). Other information about habitat, breeding, behaviour and 
vocalization are given by Brazil (1991). 

Rallus okinawae is clearly closely related to island rails of the torquatus 
group, including insignis from New Britain, and various forms occurring 
from the Philippines to Sulawesi (Celebes), the Moluccas and Irian Jaya 
(New Guinea). We consider (near) flightless okinawae to belong in the 
superspecies including torquatus (flying) and insignis (flightless) (category 
Ac), and placed by Olson (1973) in the genus Gallirallus, an opinion that 
is shared by White & Bruce (1986) and Sibley & Monroe (1990: 223). 
Diamond (1991) in his description of another new flightless species of 
Gallir alius from the Solomon Islands, discussed some problems of the 
independent evolution of flightlessness in island rails. 

Given the healthy population size of R. okinawae, we hope that a small 
sample of specimens, including skins, skeletons and tissues, will be 
collected and deposited in major collections for further study. 


(3) Calidris paramelanotos Parker 1982, South Australian Naturalist 
56(4): 63 — Price Saltfields, upper Gulf St. Vincent, South Australia. 
= ? Calidris paramelanotos (Ba). 

The holotype, collected 5 March 1977, and the paratype, collected 16 
February 1985, are in the South Australian Museum (Parker 1982). The 
very short original description (not accompanied by illustration) stated 
that the Cox's Sandpiper C. paramelanotos "resembles the Pectoral 
Sandpiper C. melanotos in size, shape of tail and pigmentation of primary 
shafts". It was said to differ from C. melanotos in several characters, 
including bill length and bill colour, leg colour, colour of pectoral 
plumage, colour of rump feathers, and other plumage characters, includ- 
ing colour of the median upper tail-coverts. The original description 
gave no information of a nature such as to suggest that the 2 specimens 
(holotype and paratype) did, indeed, represent a new biological taxon in 
the genus Calidris. No mention was made of detailed comparisons with 
any other Calidris, save C. melanotos or of the possibility of hybridization. 

Since the original observation of an unusual sandpiper in southern 
Australia by John B. Cox (1 989a) and others, a veritable flood of literature 
has been pouring forth on this putative species. In an article by Cox, 
entitled "The story behind the naming of Cox's Sandpiper" (1989b), 
the author "seeks to clarify the . . . controversy . . . that has become an 
embarrassment to Australian ornithology". We will not review here this 

F. I uilhumier, M. LeCroy & E. Mayr 272 Bull. B.O.C. 1 1 2A 

enormous literature, other than to note that little of it has appeared 
in serious scientific ornithological journals, but instead refer to a short 
piece by Monroe (1991), who listed the pertinent papers (q.v.) and who 
succinctly summarized much of the evidence. Several points need to be 
made: (1) There are 4 specimens; (2) "The breeding range is unknown"; 

(3) "The full alternate and juvenal plumages are also unknown"; (4) "All 
four specimens and most photographs . . . are intermediate in all charac- 
teristics between the Curlew Sandpiper (C. ferruginea) and the Pectoral 
Sandpiper (C. melanotos)"; (5) "It is hopeful that biochemical studies 
underway will resolve the issue with respect not only to the hybrid origin 
but also to the correct parentage" (Monroe 1991). See also Sibley & 
Monroe (1990: 240), who stated: "Present evidence is not sufficient to 
confirm or refute the hypothesis of valid species or that of hybrid origin". 

Stepanyan ( 1 990) suggested that C. paramelanotos is a hybrid between a 
male of either C. acuminata or C. melanotos and a female of Philomachus 
pugnax on the basis of morphological and behavioural characters. 
Furthermore, he suggested that the recent eastward range expansion of 
P. pugnax into the Chukotski Peninsula puts this species in sympatry with 
both C. acuminata and C. melanotos, hence the recency of the sudden 
appearance of C. paramelanotos. One of us (ML in litt. to Parker in 
1978) suggested that if the birds are hybrids, "one parent might be 
C. acuminata'' . 

For the time being, we suggest that C. paramelanotos, which is likely to 
be of hybrid origin, be maintained as a species inquirenda (category Ba). 

We strongly feel that the inclusion of "Calidris paramelanotos'' in a 
book such as Shorebirds, an Identification Guide to the Waders of the World 
(Hayman et al. 1986) is premature, given the lack of information on this 
putative new species. 


(4) Glaucidium albertinum Prigogine 1983, Rev. Zool. Afr. 97(4): 
887— Musangakye (1690 m.), Zaire. 

= ? Glaucidium albertinum (Ba). 

Five specimens of pygmy owls collected between 1950 and 1981 in 
Zaire and Rwanda formed the basis for the description of this new species. 
All 5 (including the type) are in the Koninklijk Museum voor Midden- 
Afrika (KMMA), Tervuren (holotype has number 1 14546). "Glaucidium 
albertinum is restricted to forests around the Graben (Albertine Rift) in 
Central Africa. Whereas the first two specimens came from transitional 
forest, the other three were found in mountain forest" (Prigogine 1983: 
889). Two poorly reproduced black and white photographs showing 
dorsal patterns accompany the original description. Formerly confused 
with G. castaneum, the birds included in G. albertinum differ from 

G. capense in several characters, including the pattern of the head and 
back, the barred uppertail coverts, and the brown rather than rich chest- 
nut colour. G. albertinum is more uniformly coloured on the back than is 
G. castaneum. G. albertinum has a shorter tail, and a lower wing/tail ratio 
than G. castaneum and various subspecies of G. capense. G. albertinum also 
has fewer bars on the central tail section (6—8, versus 9-1 in G. castaneum. 

Bull. B.O.C. 1 12A 273 New species 1981-90 

and 10-11 or 13 in G. capense). Prigogine (1983: 892) concluded: 
1 'Taking into account the light barring on the back of G. castaneum, 
its barred uppertail coverts and its measurements, one must consider 
castaneum as a subspecies of G. capense which may form a superspecies 
with G. albertinum." No detailed information was given about the 
geographical relationships of these 3 taxa (albertinum, capense and 
castaneum). The voice of albertinum is unknown. 

In a later paper, Prigogine (1985: 92) reviewed aspects of G. albertinum 
and confirmed its distinctness, based on morphological similarity among 
the 5 specimens, and morphological differences between them and 
G. capense and G. castaneum. (Small individual variation had been noted 
earlier — Prigogine 1983). In his Appendix (Table A. 1, p. 106), Prigogine 
(1985) indicated the status of G. albertinum as '? species'. Keith (pers. 
comm.) believes G. albertinum to be a good species but that too little 
is known to ascribe it to a superspecies, especially since its voice is 
unknown. Sibley & Monroe (1990: 179) accept G. albertinum as a full 

In view of the difficulties in the species-level systematics of owls in the 
genus Glaucidium, and given the absence of data on vocalizations and 
ranges, it seems impossible at present to decide whether G. albertinum is 
or is not an allospecies of G. capense or whether it is a species inquirenda. 
Given these uncertainties we conservatively rank it at present as Ba. 
Only further evidence will permit a decision to be made between these 


(5) Caprimulgus prigoginei Louette 1990, Ibis 132: 349 — Malenge, 
Itombwe, Kivu Province, Zaire, at 03°26'S, 28°30'E; in forest at 
1280 m altitude. 
= Caprimulgus prigoginei (Ab). 

This new species of nightjar (illustrated in a colour plate) was described 
on the basis of a single female specimen collected on 11 August 1955 by 
Prigogine's collector in the Itombwe forest in Zaire. The holotype, 
number 78975 is deposited in the KMMA. 

Chiefly on the basis of size, proportions, and colour pattern, Louette 
(1990) thought that this bird represented a new species which is not 
closely related to Caprimulgus batesi, with which it was thought to belong 
previously. After comparing this specimen with all species of African 
Caprimulgidae except C. eximius, Louette (1990: 349) concluded that "it 
does not belong to any of the known species from Africa" and added 
"Although only known from a singleton, the evidence amply justifies 
treating this distinctive nightjar as a new species". Louette (1990: 352) 
went so far as to state: "I have no hesitation in considering C. prigoginei to 
be a new species without close relatives among the known nightjars." 

This new species is unknown in life. Louette (1990: 352) listed other 
bird species collected at the type locality in order to predict what the new 
nightjar's habitat might be. 

Keith (pers. comm.) believes that Caprimulgus prigoginei is undoubt- 
edly a good species because it does not resemble any African species of 

/•' I -lullaomer, M. LeCroy & E. Mayr 21 A Bull. B.O.C. 1 12A 

caprimulgid and it does not have any shared or intermediate characters 
that would cause one to suppose it might be a hybrid. 

In view of the distinctiveness of this new species we classify it as Ab 
(new species not clearly a member of a superspecies). We hope that more 
museum specimens of this interesting new taxon will be discovered in the 
near future and that it can be studied in nature. 


(6) Melignomon eisentrauti Louette 1981, Rev. Zool. Afr. 95(1): 131 — 
c. 2 km east of Grassfield (7°30'N, 8°35'W), Mt. Nimba, Liberia. 

= ? Melignomon eisentrauti (Ba). 

This new species is based on 2 specimens. The holotype (a $ with an 
enlarged ovary) was collected in 1980 and is housed at the KMMA (No. 
80-36-A-218). The paratype (also $) is in the State Museum of Natural 
History, Stuttgart, and was collected by M. Eisentraut in 1957 on Mt. 
Cameroon. The 2 specimens of M. eisentrauti were compared to a series 
of M. zenkeri from Zaire. The original description includes very little 
comparative information and no illustrations. Apparently M . zenkeri is 
"much more greenish-yellow ventrally". A table includes only measure- 
ments of 20 M. zenkeri, which do not differ significantly from measure- 
ments of the type and paratype of eisentrauti. Louette (1981: 135) stated: 
"M. eisentrauti is likely to be allopatric of [sic] the Lower Guinean zenkeri 
and will almost certainly be found in other forest remnants between 
western Cameroon and Sierra Leone." 

Colston (1981) published, nearly simultaneously, a paper on the same 
taxon, and wrote: "A copy of this paper, proposing a new name, was sent to 
Dr M. Louette in October 1980, shortly after it had been submitted for 
publication. Dr Louette has since seen fit to describe the new honeyguide 
without informing us of his intention . . . His paper came to hand while this 
one was in proof and it has been possible to do little more than delete the 
proposed name and substitute eisentrauti for it in the text and table. ' ' Colston 
(1981) reported 1 1 specimens of eisentrauti (6 $<$ and 5 $9), and compared 
them with M. zenkeri, which he grouped with eisentrauti in a superspecies. 

Prigogine (1985) gave the status of M. eisentrauti as "species" 
(Appendix, Table A. 1 , p. 1 06), without comment. Although Keith (pers. 
comm.), Short (pers. comm.) and Traylor (pers. comm.) think that 
M. eisentrauti is a good species and that it forms a superspecies with 
M. zenkeri, it seems to us impossible at present for lack of pertinent 
biological data to decide whether M . eisentrauti is either an allospecies 
of M. zenkeri (Sibley & Monroe 1990: 44), or else a species inquirenda. 
Conservatively, we classify it for now as Ba. 


(7) Mirafra ashi Colston 1982, Bull. Brit. Orn. CI. 102(3): 107— 13 km 
north of Uarsciek, southern Somalia, 2°17'N, 45°50'E. 

= Mirafra ashi (Ab). 

This is the fourth new species of larks of the genus Mirafra to have been 
described since 1955, the others being M. williamsi MacDonald 1956 

Bull. B.O.C. 1 12A 275 New species 1981-90 

(discussed in Mayr 1971), M. sidamoensis Erard 1975 and M. degodiensis 
Erard 1 976 (discussed in Mayr & Vuilleumier 1 983). M. ashi is based on a 
series of 6 specimens "collected by Dr J. S. Ash 13 km north of Uarsciek 
( = Warsheikh), some 80 km NE of Mogadiscio, in southern Somalia on 
9 and 10 July 1981". The type is housed at the BMNH (Tring), No. B.M. 
1982-3-1 . The new species was compared chiefly with M. somalica, which 
"has been collected at Uarsciek, 2°17'N, 45°44'E" and is thus sympatric 
with it. Of comparisons with Mirafra larks other than somalica, Colston 
(1982: 107) only stated: "Comparison with BMNH material shows the 
Uarsciek larks to be similar in structure and plumage to other Mirafra 
species and closest to M. somalica" "Whereas somalica is bright 
cinnamon-rufous above, ashi is greyish-brown above with a very faint 
overlaying wash of cinnamon. It is also considerably more streaked and 
scaly looking above in general appearance than somalica" (Colston 1982: 
107). A table gave measurements of M. ashi and M. somalica and 
showed ashi to be smaller. Further brief comparison was made between 
M. sharpei, M. ashi, and M. somalica: sharpei has no white in the tail, 
whereas M. ashi has narrow white edges to outer retrices, and M . somalica 
much wider white edges. No illustrations accompanied the original 

Prigogine (1985, Appendix, Table A.l: 106) accepted M. ashi as a 
species without comments. Keith (pers. comm.) believes that M . ashi is a 
good species but that it is premature to ascribe it to a superspecies until its 
voice and behaviour are known. Sibley & Monroe (1990: 649) maintain 
M. ashi as a species. Ash (in litt. 1 June 1988) wrote that " Mirafra ashi 
[had] been looked for, but not refound". Given the difficulties of species- 
level systematics in larks of the genus Mirafra, one would have wished 
for more biological information bearing on the status of the new taxon. 
Pending such evidence, however, we keep M . ashi as a species (Ab). 


(8) Hirundo perdita Fry & Smith 1985, Ibis 127: 2 — Sanganeb Light 

House, Red Sea (19°43|'N, 37°26'E). 
= ? Hirundo perdita (Ba). 

This new species is based on a single specimen found dead on 9 May 
1984 by the junior author at the Sanganeb lighthouse, located on a reef 
"20 km northeast of Port Sudan and 14 km due east of the coast" (Fry & 
Smith 1985: 1). During a stay at Sanganeb lighthouse for 2 weeks from 30 
April 1984 to at least 9 May 1984 many Palaearctic migrants were seen or 
caught, including a number of swallows: "one House Martin Delichon 
urbica, 2 Red-rumped Swallows Hirundo daurica, up to 100 R. riparia 
per hour and up to 500 H. rustica per hour" (Fry & Smith 1985: 2). The 
type (BMNH No. 1984.5.1) consists of wings and tail only. The original 
description is illustrated by a colour plate, which shows the dead bird 
(dorsal and ventral views) before it decomposed. 

The putative new species was compared to H. spilodera, from which it 
differs in several colour characters, especially steely blue crown, blackish 
forehead and lores, grey rump, white chin, and bluish-black throat and 
upper breast. On the basis of these differences in a single unpreserved 

F. I 'uiUeumier, M. LeCroy & E. Mayr lit Bull. B.O.C. 1 1 2A 

specimen, Fry & Smith (1985) concluded that "it clearly represents a new 
form, to which we accord specific rank" (p. 2). The breeding range of the 
putative new species is unknown. 

Sibley & Monroe (1990: 579) included perdita as an allospecies of the 
Hirundo spilodera] superspecies, adding: "May be conspecific with 
some member of the H. [spilodera] superspecies". Keith (pers. comm.) 
thinks H. perdita is a good species but that it is premature to link it with 
any other species. Parkes (in litt.) is sceptical of H. perdita being a valid 
species: "strangely, considering the time and place of discovery, no 
mention was made of the (to me) strong possibility that it is a hybrid of 
Palearctic origin". Remsen (in litt.) also wondered about perdita being a 
hybrid. In view of the very incomplete nature of the unique type, we agree 
with Parkes and Remsen that a hybrid origin cannot be ruled out. 

Pending further specimens (and the postscripts in Fry & Smith 1985: 6, 
notwithstanding), we judge it prudent to treat H. perdita as a species 
inquirenda (category Ba). 


(9) Phyllastrephus leucolepis Gatter 1985, J. f. Ornith. 126(2): 155 — 
20 km NW Zwedru near Cavalla River, Grand Gedeh County, 
Liberia <6°12'N, 8°11'W). 

= Phyllastrephus leucolepis (Ab). 

This species is described on the basis of the unique type, a mummified 
specimen ('Mumienpraparation') that had been damaged by the shot and 
by ants, and is now housed at the Alexander Koenig Museum, Bonn (No. 
ZFMK 84.221). The original description was accompanied by a colour 
plate. The new species was observed several times between October 1981 
and January 1984, when the type was collected. Gatter (1985: 160, 161) 
ruled out conspecificity with the sympatric Phyllastrephus icterinus on 
several grounds, including morphological differences enhancing behav- 
ioural characteristics, especially light patches in the wing "used as an 
optical signal in the dark forest". Keith (pers. comm.) believes that 
P. leucolepis is a good species, quite unlike anything else, and that its 
nearest relative is hard to guess. Sibley & Monroe (1990: 588) accepted 
P. leucolepis as a full species. In view of the numerous sibling species 
among bulbuls, we tentatively accept the view that P. leucolepis is a 
distinct new species (Ab), but look forward to more data. 

Muscicapidae (Timaliinae) 

(10) Stachyris latistriata Gonzales & Kennedy 1990, Wilson Bulletin 
102(3): 368— at an altitude of 1530m, 11°8'N, 122°14'E, 1.1km 
SSW of the peak of Mt. Baloy, Barangay San Augustin, Munici- 
pality of Valderrama, Antique Province, Panay, Philippines. 

= Stachyris [striata] latistriata (Ac). 

A babbler of the genus Stachyris collected on 6 March 1987 from 
Mt. Baloy (Panay Island) differed sufficiently from S. striata (Luzon) 
and 5. nigrorum (Negros) to suggest that it belonged to a new species. 
Consequently an expedition was launched in 1989 to the same area, and 

Bull. B.O.C. 1 12A 277 New species 1981-90 

35 specimens of this very common species were obtained: 18 skins, 13 
skins with trunk skeletons, 3 fluid-preserved specimens, and 1 skeleton. 
Frozen tissues were also collected from 10 specimens. The type is in the 
National Museum of the Philippines (No. 16663). The paratype series 
consists of 15 specimens in the NMP and 16 in the Cincinnati Museum 
of Natural History. The original description includes a colour plate, 
2 black and white photographs of the holotype, and an extensive dis- 
cussion including details on habits and behaviour, habitat (illustrated 
with 2 black and white photographs), distribution (with a map), breeding 
(2 photographs of nest and nestlings), and vocalization. 

This careful paper leaves no doubt that the new taxon is indeed a 
distinct new member of the Stachyris [striata] superspecies (category 
Ac). Dickinson et al. (1991) also list this taxon as a full species, but 
without discussing superspecies affinities. 

Table 1 in Gonzales & Kennedy (1990: 371) gave a summary of charac- 
ter variation in the 3 taxa of the Stachyris [striata] superspecies that are 
most closely related. S. latistriata has a broader black band on the 
forehead; greenish olive crown, hind neck, mantle, and tail; broad black 
streaks on breast and flanks; and bluish olive legs and feet. The less closely 
related S. hypogrammica is discussed in the text. (p. 370). Note that 
S. nigrorum, a member of this superspecies, was described as recently as 
1 952 by Rand & Rabor. In his comment on this taxon, Mayr (1957: 29) had 
written: ''Distantly related to S. striata of the mountains of northern 
Luzon, but fully deserving specific rank". Another member of the S. 
[striata] superspecies, hypogrammica was described by Salomonsen 
(1961). Of that taxon, Mayr (1971) wrote: "This species is clearly related to 
highland species of the Philippines, striata (Luzon) and nigrorum (Negros), 
but is sufficiently different, to judge from the description, not to form a 
superspecies with them. Six other specimens were collected with the type." 

Besides the 3 species of Stachyris cited above, 3 other babbler species 
have been described from the Philippines in recent years: Napothera 
rabori from northern Luzon in 1960, Micromacronus leytensis from Leyte 
in 1962 (both reviewed by Mayr 1971: 305), and Napothera sorsogonensis 
from southern Luzon in 1967 (see Mayr & Vuilleumier 1983: 219). Yet 
another Stachyris species, rodolphei, from northwestern Siam [Thailand] 
was reduced to the status of a subspecies of Stachyris ruficeps by Zimmer 
& Mayr 1943: 257-258. It seems likely that careful explorations of little 
known areas of Asia, such as those visited by Gonzales & Kennedy in the 
Philippines, will yield yet other new Timaliinae in the future. 

Muscicapidae (Sylviinae) 

(11) Cettia carolinae Rozendaal 1987, Zool. Mededel. 61(14): 179— forest 
c. 6 km northwest of Bomaki, northwest of Saumlaki across 
Saumlaki Bay, Yamdena Island (Pulau Yamdena), Tanimbar 
Islands, South Moluccas, Indonesia, 7°53'S, 131°15'E, altitude 
70 m. 

= Cettia carolinae (Ab) 
The type series includes, besides the holotype, 6 other specimens, 

collected by the author during field work on Yamdena Island between 23 

F. I 'uilleumier, M. Let 'toy & E. Mayr 278 Bull. B.O.C. 1 12A 

August and 8 November 1985 and are housed at the Rijksmuseum van 
Natuurlijke Historie, Leiden. The habitat, in primary monsoon forest, 
and second growth, is illustrated by 3 black and white photographs. One 
colour photograph and 2 black and white photographs illustrate living 
birds that were later collected. Because the systematics of warblers of the 
genus Cettia are difficult, the author not only made extensive compari- 
sons of skins of other Cettia species [C.fortipes, C. vulcania, C. (diphone) 
seebohmi, C. (Psamathia) annae, C. (Vitia) ruficapilla, and C. (Vitia) 
parens], but also used evidence from vocalizations from several Cettia 
taxa. In plumage characters, especially colour, Cettia carolinae resembles 
southwest Pacific C. ruficapilla badiceps and C. r. castaneoptera more than 
closer geographic neighbours like C. vulcania everetti from Timor. 

On the basis of vocal characters, C. carolinae also seems to be more 
closely related to Pacific taxa of the C. ruficapilla group (formerly in the 
genus Vitia but merged in Cettia by Orenstein & Pratt 1983). However, 
vocalizations as depicted in Fig. 12 of Rozendaal's paper seem to ally 
carolinae with fortipes davidiana. The description of this undoubted new 
species is thorough and carefully prepared and Rozendaal has pointed out 
areas in which further work is necessary before superspecies affiliations 
can be worked out. A map illustrating the distribution of the various taxa 
would have helped greatly. 

Sibley & Monroe (1 990: 609) accepted C. carolinae as a full species, and 
we do so tentatively (Ab). Further data are needed to clarify superspecies 

(12) Cichlornis llaneae Hadden 1983, Bull. Brit. Orn. CI. 103(1): 23— 
Crown Prince Range, 5000 ft (1550 m), central Bougainville Island, 
North Solomons Province, Papua New Guinea, c. 6°19'S, 155°30'E. 

= Cichlornis [whitneyi] llaneae (Ac). 

The type specimen of this new thicket warbler was collected by 
Hadden (1983) on 17 June 1979, and is housed at the AMNH (No. 
824713). A nest and egg were also collected, and are at the AMNH. This 
distinct new taxon of the genus Cichlornis is allopatric and different 
from C. w. whitneyi (Espiritu Santo), C. w. turipavae (Turipave), and 
C. grosvenori (New Britain). Little is known about these birds, which are 
represented by very few specimens in museum collections. Diamond (in 
litt.) suggested the possibility that an undiscovered Cichlornis exists in 
the mountains of New Ireland. 

Whether Cichlornis, Ortygocichla, Trichocichla, Buettikoferella and 
Megalurulus are all congeneric, as proposed by Orenstein (in Hadden 
1 983), remains to be determined, a view shared by Diamond (in litt.). Mayr 
(in Mayr et al. 1986: 47) considered C. whitneyi, llaneae and grosvenori as 
separate species, not included in a superspecies (see also Ripley 1985). 
Sibley & Monroe (1990: 625) included these 3 taxa as allo-species of the 
[whitneyi] superspecies, a view with which 2 of us concur (category Ac). 

Muscicapidae (Malurinae) 

(13) Malurus campbelli Schodde & Weatherly, in Schodde 1982, The 
Fairy Wrens: A Monograph of the Maluridae, Lansdowne Edition, 

Bull. B.O.C. 1 12A 279 New species 1981-90 

Melbourne: 32 — Bosavi, Southern Highlands Province, Papua New 
Guinea, 800 m altitude 6°24'S, 142°50'E. 
= Malurus grayi campbelli (Bb). 

The formal description of M. campbelli was published in January 1983 
by Schodde & Weatherly in Emu 82 (suppl.): 308, [even though volume 
82 carries 1982 as year of publication]; but the new taxon was actually 
confusingly 'described' earlier as an entry by Schodde & Weatherly in 
Schodde's monograph of the fairy wrens, copyrighted in 1982, as cited 
above. A colour plate illustrated the putative new taxon, but no type 
was designated. All this confusion is regrettable. Also regrettable is the 
fact that the description (whether the one in 1982 in Schodde's book, or 
the one in 1983 in the Emu supplement) was not based on a museum 
specimen, but on live birds and photographs. The putative male in a 
photograph to be distributed to various museums was designated as the 
type in the 1 983 paper. At the time of writing this, no such photograph has 
been received at the AMNH. Only later were specimens collected and 
described (Schodde 1984). 

Originally, in 1980, 2 birds were caught in mist nests by R. W. 
Campbell, photographed, and released. In 1981, 3 additional birds were 
banded and released. Then in 1982, 5 birds (2 $3, 1 $, 2 fledglings) were 
collected by R. W. Campbell and R. D. Mackay at the type locality. Four 
of these birds are housed at the Papua New Guinea Museum and Art 
Gallery, Port Moresby, and one (subadult male) is on permanent loan at 
the Australian National Wildlife Collection, CSIRO, Canberra (No. 
26467). To compound the problems created earlier, and as Schodde 
(1984: 249) wrote: ''Regrettably, none of the adults can be identified as a 
syntype (or selected as a lectotype) because none is from the banded birds 
on which the original description was based. That description first 
appeared in 'The Fairy Wrens: A Monograph of the Maluridae' (Schodde 
1982), and takes its date from the issuing of the first numbers of that work 
in August 1982". 

Originally, M. campbelli was thought by Schodde & Weatherly (1982, 
1983) to be closely related to the allopatric M. grayi, "with which it forms 
a superspecies" (Schodde & Weatherly 1983: 308), differing from it in 
several colour characters and in its smaller size. In the 1984 paper, how- 
ever, Schodde (1984: 250) thought that M. campbelli also "seems to have 
links as close to Wallace's Wren Sipodotus wallacii as to any other member 
of Malurus; and the corollary, that Sipodotus is closer to M . campbelli-grayi 
than to any other group in Malurus , seems even clearer". 

Sibley & Monroe (1990: 424) included M. grayi and M. campbelli in the 
M. [grayi] superspecies. Mayr (in Mayr et al. 1986: 393) considered 
campbelli as a subspecies of grayi. Recently, LeCroy and Diamond (ms) 
have been able to compare 32 of the 37 known specimens of Malurus grayi 
and M. campbelli. Their as yet unpublished study allowed them to recog- 
nize "the previously unappreciated geographic and individual variation 
in M. grayi, as well as to confirm the reality of certain previously reported 
sex-related differences that had been questioned". Beehler et al. (1986) 
regarded campbelli as a race of M. grayi in their recently published field 
guide to New Guinea birds on the basis of this analysis. We follow the 
same treatment here (Bb). 

F. Vuilleumier, M. LeCroy & E. Mayr 280 Bull. B.O.C. 1 1 2A 

(14) Gerygone ruficauda Ford & Johnstone 1983, Western Austr. Nat. 

15: 133 — "Thirteen Mile River", Rockingham Bay, Queensland. 
= Gerygone chrysogaster (Be). 

This new species of Gerygone was based on 3 specimens, 2 in the 
Australian Museum, Sydney (the type is number 0.17290) and one in the 
AMNH. It was said to be closest to G. magnirostris and G. chrysogaster. 
Schodde (1985) reduced G. ruficauda to the synonomy of G. chrysogaster, 
a view accepted by Sibley & Monroe (1990: 443). Some ornithologists 
(e.g. Boles, in litt.) even doubt that the specimens can be identified. We 
place it in category Be (synonyms). 

Incredibly, in this day and age, and given the profound experience of 
the late senior author in systematic and evolutionary biology, this puta- 
tive new species in a difficult Australasian genus was described on the 
basis of 3 old and uncertainly labelled specimens. The wording smacks of 
an earlier era in ornithology, now past and gone: "Though there is some 
doubt regarding the exact collecting localities of these specimens, they are 
so distinct and yet uniform in morphology, a description of a new taxon is 
warranted" (Ford & Johnstone 1983: 133). 

Muscicapidae (Platysteirinae) 

(15) Batis occultus Lawson 1984, Bull. Brit. Orn. CI. 104(4): 145— 

Grassfield, Mt. Nimba, Liberia (7°30'N, 8°35'W), altitude 550 m. 
= Batis poensis occulta (Bb). 

This is the second new species to be described from Mt. Nimba in 
the 1981—1990 period (see Melignomon eisentrauti earlier). Batis occultus 
was described on the basis of 13 specimens (Pincluding the type) from 
Ivory Coast, Cameroon, Nigeria, Ghana and Liberia. The type, from 
Liberia, is housed at the BMNH, number 1977.20.2078. Mainland 
B. occultus differs from the insular populations (B. poensis) from 
Fernando P6 in colour and size. Mainland occultus is slightly smaller than 
insular poensis and has a conspicuous white supercilium that is lacking in 

Lawson (1984: 145) said "It is here contended that the colouration 
differences between them [insular and mainland populations] are suf- 
ficiently marked for them to be considered distinct species". Keith (pers. 
comm.) thinks that B. occultus forms a superspecies with B. poensis. 
Sibley & Monroe (1990: 503) treated occultus , poensis and minulla as allo- 
species of the B. [minulla] superspecies. Traylor (in litt.) "finds this 
[taxon] hard to accept as a species", and "would accept occultus as a 
subspecies of poensis, but not as a species unless fresh Cameroon material 
shows all the differences". We agree with Traylor that occultus is best 
considered a subspecies of poensis (Bb). 

Note that, following Clancey (1989) occultus should be spelled occulta. 


(16) Nectarinia rufipennis Jensen 1983, Ibis 125(4): 447 — Mwanihana 
Forest Reserve, Uzungwa Mountains, above the village Sanje, 

Bull. B.O.C. 1 12A 281 New species 1981-90 

Kilombero District, Morogoro Region, eastern Tanzania. Altitude 
1000 m. 
= Nectarinia rufipennis (Ab). 

This new sunbird was described on the basis of a male (holotype, in 
the Zoological Museum, Copenhagen, No. 8.12.1981.1) and a female (in 
the BMNH, No. 1981.9.7) collected in 1981 in a remote area of rain- 
forest in eastern Tanzania. The new birds (illustrated in a colour plate) 
were compared to a variety of African sunbirds of the genus Nectarinia, 
including the N. chalybea species-group, the N. afra superspecies, and 
the N. regia superspecies. "The most remarkable [differences shown by 
N. rufipennis] are the bronzy throat patch of the male and the rufous 
edges of the flight feathers of both sexes, characters which appear unique 
among African sunbirds" (Jensen 1983: 449). In another, popular, 
article, Jensen (1985) published a colour photograph of a female, gave 
details about the original discovery of this new species, and indicated 
that during a subsequent expedition, he found that the new species was 
abundant from c. 4000—6000 feet, in montane forest habitat with lichens 
and mosses and epiphytic plants growing on trees. The area of this 
habitat in Mwanihana Forest "encompasses perhaps 20 square miles" 
(Jensen 1985: 21). 

Sibley & Monroe (1990: 666) wrote: "Relationships unclear; a unique 
species with no certain affinities". Keith (pers. comm.) believes that 
N. rufipennis is very distinctive and not clearly allied to any other sunbird 
species. We agree that this new sunbird is a valid species with no clear 
affinity to members of an existing superspecies (category Ab). 


(17) Meliphaga hindwoodi Longmore & Boles 1983, Emu 83(2): 59 — 

Massey Creek, Clarke Range, Queensland (21°04'S, 148°35'E). 
= Meliphaga [frenata] hindwoodi (Ac). 

This new species of honeyeater is described on the basis of 25 speci- 
mens, deposited at the Australian Museum and the Queensland Museum. 
The holotype is No. 0.17574 in the Queensland Museum. M. hindwoodi 
appears to be restricted to the Clarke Range, 80 km west of Mackay, 
Queensland. It differs from allopatric M. frenata, which occurs on the 
Atherton Tableland (Australia), and from M. subfrenata (New Guinea 
highlands), in having more grey in its plumage and streaked underparts. 
Comparisons of similarities and differences between M. hindwoodi and 
its relatives frenata and subfrenata, as well as chrysops and obscura, are 
carefully made and illustrated by photographs, drawings and tables. 
Longmore & Boles (1983) proposed a reconstruction of vegetational 
sequences in Australia and New Guinea to help explain the evolution of 
taxa in the M. frenata species-group. 

Sibley & Monroe ( 1 990: 431) accepted hindwoodi as an allospecies of the 
Lichenostomus [frenatus] superspecies. For an explanation of their use of 
the generic name Meliphaga instead of Lichenostomus, see Longmore & 
Boles (1983: 60). We believe hindwoodi to be an allospecies of frenata 
(category Ac), and we agree that the Meliphaga-Lichenostomus complex 
needs more study. 

F. I 'uilleumier, M. LeCroy & E. Mayr 282 Bull. B.O.C. 1 1 2A 

Ploceidae (Ploceinae) 

(18) Ploceus burnieri Baker & Baker 1990, Bull. Brit. Orn. CI. 110(1): 
52— Ifakara 08°08'S, 36°40'E, in Morogoro Region, east central 
Tanzania, on the northern bank of the Kilombero River, 320 km 
southwest of Dar es Salaam, altitude 250 m. 

= Ploceus burnieri (Ab). 

This new weaver was described on the basis of 4 specimens (2 <$<$ and 
2 99). The cJ 'holotype' ( = syntype) is deposited at the BMNH, No. 
1989-7-1, as is the 9 'holotype' ( = syntype) No. 1989-7-2. The 2 para- 
types are deposited at the University of Dar es Salaam Museum of 
Biology. The original description includes a colour plate painted from the 
cJ and 9 syntypes and photographs of live birds. The new weaver was 
observed breeding in riverside swamps containing Phragmites. A nest was 
collected and deposited at the BMNH. The authors compared P. burnieri 
with 57 other taxa of Ploceus, especially P. taeniopterus , P. castanops and 
P. subaureus. Baker & Baker (1990: 58) concluded: "We hesitate to 
attempt a systematic position for this species. It may well prove inter- 
mediate between the 'Masked Weavers' and P. castanops, although 
clearly the nest is closer to that of P. subaureus. " In spite of the careful 
description of the new species, and of the extensive comparisons, it is 
difficult to evaluate the biological validity of this putative new Ploceus. 
The possibility of a hybrid population is discounted: "The large sample 
size of P. burnieri and its isolation from similar species does not suggest a 
hybrid population" (Baker & Baker 1990: 56). The "large sample size" 
consists, in fact, of only 4 specimens, and some birds handled live: hardly 
enough data to interpret potential variability of hybrids. In view of the 
great difficulties posed by the systematics of Ploceus species, we keep 
P. burnieri as a distinct species, (Ab), but stress that only further series of 
specimens and more extensive biological data will resolve its status. 

(19) Ploceus victoriae Ash 1986, Ibis 128: 331 — Entebbe, Uganda, 
0°04'N, 32°28'E, altitude 1200 m. 

= ? Ploceus victoriae (Ba). 

This new Ploceus weaver was described on the basis of the unique 
holotype, a male collected 20 March 1983 and deposited at the BMNH, 
(No. 1985.1.29). The female is still unknown. "Although the specimen is 
unique, other individuals are known to exist in the field, and it is desirable 
to describe this as a new taxon at full specific level" (Ash 1986: 331). 
This species is somewhat similarly marked (facial pattern) as Ploceus 
taeniopterus , P. melanocephalus , P. castanops and P. velatus (diagram- 
matically illustrated), but seems to have a different wing formula. 
Furthermore, "P. victoriae differs markedly from taeniopterus in being a 
non-colonial and solitary species" (Ash 1986: 335). Ash (1986: 336) 
believed that morphological characters and nesting behaviour differences 
justify separating this specimen as a full species, and stated that it "can 
be regarded as a member of a superspecies including melanocephalus, 
taeniopterus, jacksoni, dicrocephalus and intermedius" . He discarded the 
possibility of hybridization, chiefly on the ground that: "The probability 
of seeing several hybrids looking alike in the same area in the course of 
one year seems to be highly unlikely, and would appear to indicate that 

Bull. B.O.C. 1 12A 283 New species 1981-90 

victoriae is not a hybrid. Also, at no time were any mixed pairs seen in the 
colonies of breeding Ploceids, which often contained several species" 
(Ash 1986: 335). 

Louette (1987) has questioned the specific status of victoriae , in a 
critique of Ash's (1986) description, in which he pointed out that 
this specimen could be the result of several hybrid combinations 
(P. castanops x P. melanocephalus fischeri or P. castanops x P. jacksoni). 
Louette (1 987: 405) also points out that several Ploceus species breeding at 
Entebbe have been found breeding in colonies, "but sometimes solitarily 
or a couple together". Thus the solitary nesting behaviour of P. victoriae, 
based on limited field evidence, might not be as significant as Ash (1986) 
suggested (see also Ash 1987 in reply to Louette 1987). 

Although Sibley & Monroe (1990: 683) included victoriae in the Ploceus 
[ taeniopterus J superspecies, they also stated that victoriae is "possibly a 
subspecies of P. taeniopterus or some other species of 'masked weaver' ". 
At the end of his paper, Ash (1986: 336) wrote that "without more study 
and more specimens of victoriae [its status] is largely conjecture". Indeed, 
we feel that there is too little evidence in this case, and for the moment 
maintain P. victoriae as a species inquirenda (category Ba). 

(20) Ploceus ruweti Louette & Benson 1982, Bull. Brit. Orn. CI. 102(1): 
26 — Kinsamba, near the eastern edge of the maximum level of Lake 
Lufira(i.e. Lake Shangalele, or Tshangalele — cf. Times Atlas, 1975: 
203, at 10°50'S, 27°03'E, and map in Ruwet 1963: facing 60), Zaire. 

= Ploceus [reichardi] ruweti (Ac). 

The unique holotype, "a male in almost complete breeding dress", 
was probably collected in March 1960, and is now kept in the KMMA 
(No. 113379). This specimen "has been compared by both of us with 
every conceivable form of Ploceus (males in breeding dress), both in 
the KMMA and in the British Museum (Natural History)" (Louette & 
Benson 1982: 25—26). The specimen is illustrated, together with a male of 
P. reichardi, in a black and white photograph. Other photographs in the 
original description include a nest attributed to P. ruweti, a colony of nests 
attributed to P. ruweti, and the typical habitat (swamp) of P. ruweti in the 
Lufira delta. Louette & Benson (1982) make a good case to suggest that 
P. ruweti is a member of the reichardi group, including also P. reichardi 
and P. katangae (with upembae as a subspecies). This group of swamp- 
dwelling allopatric forms, seem to form a superspecies. Sibley & Monroe 
(1990: 683) treated these 3 forms as members of the P. [reichardi] super- 
species. Traylor {in litt.) "would have to accept the conclusions" of 
Louette & Benson (1982). We feel that this treatment seems reasonable 
(hence our classification as Ac), but given the incomplete information 
available to date on these birds, we emphasize that the possibility that 
P. ruweti is a subspecies of reichardi has not been sufficiently addressed. 

Ploceidae (Viduinae) 

(21) Vidua raricola Payne 1982, Misc. Publ. Mus. Zool., Univ. Michigan, 
No. 162: 16— Banyo, Cameroon, 6°45'N, 11°50'E, altitude 1050 m. 

= Vidua raricola (Ab). 

F. I 'uiUeuniier, M. LeCroy & E. Mayr 284 Bull. B.O.C. 1 12A 

The holotype, a male in breeding plumage, housed at the University of 
Michigan Museum of Zoology (number 204008), was collected by Payne 
on 6 November 1980. Other material used to describe V. raricola include 
1 7 specimens from Cameroon, one from Sierra Leone, and 2 from Ghana. 
"The species name raricola refers to the affinity of this brood parasite 
species for its foster species and song model, the Black-bellied Firefinch 
Lagonosticta rara" (Payne 1982: 33). V. raricola differs from other indigo- 
birds Vidua "by the mouth pattern of the immature birds, which mimic 
the mouth pattern of nestling Black-bellied Firefinches Lagonosticta 
rara" (Payne 1982: 17). Males mimic the songs of L. rara. It seems 
impossible to identify some individual specimens of Vidua unless their 
host species is known. Also, variability of plumage colour in V. raricola 
matches that of other Vidua species. This clearly presents exceptional 
difficulties for systematics. But, as Payne (1982: 17-18) stated: "the 
morphogenetic uniqueness of certain young indigobirds in mimicking the 
mouth pattern of L. rara, the restriction of these young to the localities 
where L. rara occur and where adult male indigobirds mimic the songs of 
L. rara, and the morphogenetic distinctiveness of these males from other 
locally sympatric male indigobirds that mimic other species of firefinches 
in Cameroon and in Sierra Leone together indicate that the population 
[raricola] behaves as a species distinct from the others". As Payne (1982: 
18, 22) himself pointed out: "This diagnosis recognizes that it may 
be impossible to identify to species those birds in regions where the 
song behaviour is unknown." Female and juvenile V. raricola are 
indistinguishable from similar plumages of other species of indigo birds. 

In Cameroon, Payne (1982) found 3 sympatric species of Vidua, 
V. raricola mimicking Lagonosticta rara, V. funerea mimicking 
L. rubricata, and V. wilsoni mimicking L. rufopicta. "No habitat differ- 
ences were apparent between the green V. raricola and blue V. funerea at 
Banyo; the birds were on neighbouring territories in scrub at the edge of 
fields cultivated for manioc and pineapple" (Payne 1982: 26). 

V. raricola occurs together with its host species Lagonosticta rara from 
Sierra Leone to Ghana, Nigeria and Cameroon, and probably also in 
parts of Zaire and of Sudan. 

Sibley & Monroe (1990: 700) accepted V. raricola as a full species. 
Traylor (in litt.), who has studied indigobirds, made the point that 
V. raricola (and the next species V. larvaticola) must be considered good 
species "if you accept Payne's thesis that the species of Vidua are each 
obligate nest parasites on a single species of Lagonosticta, and that they 
can be identified by mimicking the songs of their respective hosts, andby 
the juvenals having the same palatal markings" (italics ours). We classify 
raricola as Ab, a species not clearly a member of a superspecies. 

(22) Vidua larvaticola Payne 1982, Misc. Publ. Mus. Zool., Univ. 

Michigan, No. 162: 33— Zaria, Nigeria, 11°10'N, 7°40'E. 
= Vidua larvaticola (Ab). 

The holotype, a male in breeding plumage, kept in the University of 
Michigan Museum of Zoology (number 216994), was collected by Payne 
on 6 August 1968. Additional specimens used to describe V. larvaticola 
include 21 birds from Nigeria. "The species name larvaticola describes 

Bull. B.O.C. 1 12A 285 New species 1981-90 

the affinity of this indigobird for its host species Lagonosticta larvata" 
(Payne 1982: 41). 

"The species V. larvaticola is characterized by its species-specific 
mimicry of the Black-faced Firefinch Lagonosticta larvata" (Payne 1982: 
34). As in V. raricola, it is impossible to identify some specimens of 
V. larvaticola, especially females and juveniles, but males also, unless 
they were collected with their host species (males vary regionally from 
green to blue in colour). Immature V. larvaticola have mouth markings 
that mimic those of L. larvata. Further, male V. larvaticola mimic the 
vocalizations of L. larvata. 

Payne (1982: 36—39) found local sympatry in Nigeria between Vidua 
chalybeata (and its host Lagonosticta senegald), V. larvaticola (and host 
L. larvata), and V. wilsoni (and host L. rufopicta). V. larvaticola occurs in 
Nigeria and Cameroon, and probably also locally in other west African 
countries (The Gambia, Guinea-Bissau, Guinea, Mali, Ivory Coast, 
Ghana, Togo), as well as in Sudan and elsewhere in central Africa. 
Payne's (1982) Fig. 21 illustrates the distribution of V. larvaticola and its 
host Lagonosticta larvata. 

As for Vidua raricola, Payne's (1982) evidence strongly suggests 
specific distinctness of V. larvaticola, a view adopted by Sibley & Monroe 
(1990: 700). Although more work is needed to establish clearly the status 
of V. raricola, we classify it as Ab. 



(23) Tachyeres leucocephalus Humphrey & Thompson 1981 , Occ. Papers 
Mus. Nat. Hist. Univ. Kansas, No. 95: 3 — Puerto Melo, Provincia 
de Chubut, Argentina (45°01'S, 65°50'W). 
= Tachyeres [pteneres] leucocephalus (Ac). 

The holotype, an adult male, no. 52694 in the Museo Argentino de 
Ciencias Naturales (MACN), Buenos Aires, Argentina, was collected on 
24 September 1979 by Humphrey & Thompson (1981). The description 
is based on material deposited at the MACN (one skin and partial skel- 
eton, the holotype); Southwestern College, Winfield, Kansas (6 skins and 
partial skeletons); and Museum of Natural History of the University of 
Kansas, Lawrence (25 complete skeletons). T. leucocephalus is 'abundant' 
at the type locality, Puerto Melo, "and presumably other localities with 
rocky shorelines along the coast of Chubut" (Humphrey & Thompson 
1981: 8); elsewhere in the paper, the authors mention the species having 
been photographed at Punta Tombo and Camarones, and state that 
T. leucocephalus "probably occurs in appropriate habitat along the coast 
of Chubut from Bahia Bustamante north perhaps as far as Puerto 
Madryn and Peninsula Valdez" (p. 7). See Beno (1982) for a popular 
account of the discovery of this species. 

"Tachyeres leucocephalus is distinct from all known species in the genus 
[pteneres, brachypterus and patachonicus] in terms of various combi- 
nations of characters, including body weight, proportions of certain 
measurements, shape of humerus and posterior region of sternum, and 

F. I -utlleumier, M. LeCroy & E. Mayr 286 Bull. B.O.C. 1 12A 

colouration of the feathering of the head and neck in various plumages" 
(Humphrey & Thompson 1981: 5). A colour plate illustrates head 
plumages of males and females, in various moult stages, and of ajuvenal. 

On the basis of a phylogenetic study, Livezey (1986) concluded that 
the 3 flightless taxa of Tachyeres were a monophyletic assemblage, 
within which T. leucocephalus and T. brachypterus (Falklands) were the 
most closely related taxa (sister species). Livezey ( 1 986) proposed a model 
of differentiation, according to which allopatric speciation between 
proto-leucocephalus and proto-brachypterus was the latest of several 
postulated vicariance events. In another study, Corbin et al. (1988) 
analyzed steamer-ducks by means of electrophoretic characters, and 
confirmed the close relationships of the 3 flightless taxa, and the sister- 
species relationship of brachypterus and leucocephalus. Corbin et al. 
(1988: 779) speculated that "the divergence of lineages leading to 
T. brachypterus and T. leucocephalus would have occurred about 13,000 
years ago". 

Sibley & Monroe (1990: 32) placed the 3 flightless taxa of Tachyeres 
in a single superspecies. Humphrey (in litt.) felt that they are too dif- 
ferent to be included in a superspecies. One of us (F V) recently saw 
T. leucocephalus at the type locality and Cabo dos Bahias, and feels 
that still more study is needed to clarify relationships between it and 
T. pteneres. Given the taxonomic problems posed by the different popu- 
lations of Tachyeres, we tentatively place the 3 flightless steamer ducks 
in a single superspecies T. [pteneres] ', and hence classify T. leucocephalus 
as Ac. 


(24) Pyrrhura orcesi Ridgely & Robbins 1988, Wilson Bulletin 100(2): 
174 — c. 9.5 road km west of Pinas, altitude c. 900 m, 3°40'S, 
79°44'W, Prov. El Oro, Ecuador. 

= Pyrrhura [melanura] orcesi (Ac). 

The holotype, an adult male, is deposited in the Academy of Natural 
Sciences of Philadelphia (ANSP) (No. 177523). Sixteen additional speci- 
mens exist, 14 at the ANSP, one in the BMNH, and one in the Museo 
Ecuatoriano de Ciencias Naturales in Quito. The 17 specimens come 
from 2 localities, in Provinces El Oro and Azuay. P. orcesi (illustrated by a 
colour plate in the original description) is allopatric with various popu- 
lations of P. melanura, from which it differs in having a red forehead, 
obsolete scaling on the breast, and greener crown (variation illustrated in 
a colour plate including both species and their geographic distribution). 
P. orcesi appears restricted geographically and occurs in humid mid- 
montane forest between 600 and 1100 m. (except that the BMNH 
specimen was collected at 300 m). 

Forshaw (1989: 493) treated orcesi as a full species. Sibley & Monroe 
(1990: 126) treated it as a member of the P. [melanura] superspecies, and 
we treat it likewise here (Ac). 

(25) Amazona kawalli Grantsau & Camargo 1989, Rev. Brasil. Biol. 
49(4): 1018— Rio Jurua, Amazonas, Brazil (region circumscribed in 

Bull. B.O.C. 1 12A 287 New species 1981-90 

a radius of c. 75 km from Seringal de Mato Piri, along the right bank 
of the Rio Jurua, downstream from the town of Eirunepe, on the left 
bank of the Rio Jurua [6°38'S, 69°50'W]). 
= ? Amazona kawalli (Ba). 

The description of this new species is based on 3 birds, the holotype (a 
female, housed in the Museum of Zoology of the University of Sao Paulo 
(MZUSP), number 2727) collected in 1902, and 2 paratypes (one, female, 
in MZUSP, number 3478, also collected in 1902; the second, a male, in 
the collection of Rolf Grantsau, number 7577, from Santarem, Para, 
collected in 1970). This new taxon has previously been confused with 
A. farinosa. It differs from farinosa in bill colour, a white patch of skin 
at the base of the bill, an ashy grey ocular ring, pale green carpal joint 
without any trace of red, generally green colour, external rectrices with 
red at the base of the inner vane, restricted amount of pale green at distal 
tip of central rectrices. Two live birds are also cited by Grantsau & 
Camargo (1989), in Nelson Kawall's collection. The new bird was com- 
pared to a series of 25 Amazona j .farinosa. A colour plate accompanies the 
original description. 

Grantsau & Camargo (1990) essentially re-published their 1989 
description in the semi-popular German journal Trochilus, with the same 
colour plate (but less well-produced), but with the addition of a table 
of measurements of A. kawalli and A. f. farinosa, and a map of the 
distribution of A. kawalli, showing the 2 localities, 1700 km apart. 

We feel that there is not enough evidence at present to decide what the 
status of this form is, hence our classification as Ba. 


(26) Otus marshalli Weske & Terborgh 1981, Auk 98(1): 1— Cordillera 
Vilcabamba, 12°38'S, 73°36'W, altitude 2180 m., Provincia de la 
Convencion, Departamento de Cuzco, Peru. 
= Otus marshalli (Ab). 

The holotype is an adult male kept at the AMNH (number 824160). 
Eight specimens were available for the original description, all collected 
from c. 1920-2240 m in the northern Cordillera Vilcabamba, Cuzco, 
Peru. Since the original description, the species has been found farther 
north, in the Cordillera Yanachaga (Schulenberg et al. 1984). In the 
Cordillera Vilcabamba, this owl seems to be common and reached its peak 
abundance between 2130 and 2190 m, where it was "the 29th most com- 
monly netted bird species among a total of 5 3 " (Weske & Terborgh 1981: 
4). Its habitat is cloud forest with a luxuriant understorey, including a 
profusion of clinging bamboo. The new owl differs from other Neotropi- 
cal owls, except the Central American species O. barbarus and O. clarkii, 
in the barred and streaked underparts. No Andean taxon appears to be 
closely related to O. marshalli. The morphological differences between 
O. marshalli, O. barbarus and O. clarkii are rather well marked. It is thus 
unclear whether O. marshalli should be included in a superspecies with 
barbarus and clarkii. 

Further problems are raised by the description of O. peter soni (see 
below, under 27), which Fitzpatrick & O'Neill (1986) compared with 

F. I 'uilleunuer, M. Lei "ray & E. Mayr 288 Bull. B.O.C. 1 1 2A 

mar shall i and other Otus spp. (especially ingens, colombianus and 
watsonii). These 4 species appear to form a species-group of brown-eyed 
Otus. Note that Fitzpatrick & O'Neill (1986) did not discuss the affinities 
of O. clarkii and O. barbarus. 

Marshall & King (1988: 335) treated O. marshalli as a full species; 
Sibley & Monroe (1990: 173) included marshalli and petersoni in a super- 
species, an action that may be premature. That O. marshalli is a valid 
species is not in question, but whether it belongs to a superspecies and 
with what other species is as yet uncertain. Thus our tentative classifi- 
cation of this bird as Ab. It is unfortunate that the voice of O. marshalli 
is unknown. 

(27) Otus hoyi Konig & Straneck 1989, Stuttgarter Beitr. Naturk., Ser. A 
(Biol.), No. 428: 4 — La Cornisa, c. 40 km north of the town of Salta, 

= Otus atricapillus hoyi (Bb). 

The type, a bird collected by G. Hoy in 1987, is in the ornithological 
collection of the Staatliches Museum fur Naturkunde in Stuttgart 
(number SMNS 62849); one paratype is in the Museo Argentino de 
Ciencias Naturales in Buenos Aires, and 8 others in the Instituto 
Miguel Lillo in Tucuman. These 10 birds differ from O. choliba and 
O. guatemalae in several characters (illustrations of skins and sonagrams 
of vocalizations are provided in the description), and in colour and pattern 
resemble more closely Central American O. barbarus, O. marshalli from 
Peru (see number 26 above), or else an Otus from southern Brazil. The 
vocalizations of Otus guatemalae from Peru appear closer to those of 
O. hoyi than those of other Otus spp. O. hoyi lives in wet montane forest 
between c. 1000 and 2600 m, in areas with dense undergrowth. Konig & 
Straneck (1 989) mentioned the similarity in habitats between O. hoyi and 
O. marshalli. 

In a later paper, Konig (1991) examined in detail the relationships 
of O. atricapillus , O. sanctaecatarinae (parapatric) and O. hoyi (allo- 
patric), especially through comparisons of vocalization. Together 
with O. guatemalae, Konig (1991: 213) placed these 3 forms in the 
O. [atricapillus] superspecies. On the basis of this additional evidence, 
one could either accept his classification or consider hoyi as a sub- 
species of atricapillus. For the present we favour the latter designation 

(28) Otus petersoni Fitzpatrick & O'Neill 1986, Wilson bulletin 98(1): 
2 — Cordillera del Condor, above San Jose de Lourdes, Dept. 
Cajamarca, Peru, 5°02'S, 78°51'W, altitude 1950 m. 

= Otus colombianus petersoni (Bb). 

The holotype is an adult male housed at the AMNH (No. 824049). 
Nine additional specimens are paratypes. The new species occurs at 4 
localities, 2 in southern Ecuador and 2 in northern Peru. An additional 
(11th) specimen is a Bogota trade skin (at the Academy of Natural 
Sciences of Philadelphia). A colour plate accompanies the original 

Bull. B.O.C. 1 12A 289 New species 1981-90 

The new species lives in subtropical forest, and is sympatric at 3 of the 4 
localities with O. ingens. After a detailed analysis of morphology and 
vocalizations, Fitzpatrick & O'Neill (1986) concluded, convincingly, that 
O. peter soni is the sister-taxon of O. colombianus , from the eastern Andes 
of Colombia and Ecuador. ''In plumage pattern and colour, colombianus 
and peter soni are so nearly alike as to suggest they could be conspecific" 
(Fitzpatrick & O'Neill 1986: 9). They prefer to treat them as distinct 
species, but they "emphasize that based upon present data the question 
cannot be settled unequivocally". Sibley & Monroe (1990: 173) treated 
peter soni and marshalli as members of a superspecies. Marshall & King 
(1988: 335) treated peter soni as a subspecies of colombianus, and we are 
inclined to agree with this placement (Bb). 


(29) Asthenes luizae Vielliard 1990, Ararajuba I: 121 — c. 1100m. altitude, 

serra do Cipo, municipio de Jaboticatubas, Minas Gerais, Brazil. 
= ? Asthenes luizae (Ba). 

This new Asthenes was described on the basis of 2 specimens. The 
holotype, an adult male, "will be deposited at the MZUSP when the work 
in progress is completed" (Vielliard 1990: 121). At present the holotype is 
in F. Lencioni's collection (number 349). The paratype, an immature 
male, is also in F. Lencioni's collection (number 568). Thus, the accessi- 
bility of the type specimen is in doubt, and we strongly deplore the prac- 
tice of having specimens of (putative) new taxa in private collections, 
as both appear to be in this instance. These birds were collected in 
December 1985 and December 1988 in the Serra do Cipo, Minas Gerais. 
A coloured plate of the new bird has been prepared by F. Lencioni (but 
has not been published — F. Lencioni in litt.). A subsequent paper is 

The original description only states that F. Lencioni recognized that 
the specimen he collected in 1985 "belonged to the genus Asthenes and 
that it was a new species" (Vielliard 1990). Nowhere in the original 
description did the author state whether comparisons had been made 
between the 2 type specimens and any other Furnariidae, including 
Asthenes. It is thus impossible to make any statement about Asthenes 
luizae on the basis of Vielliard's (1990) description. 

More or less simultaneously, Pearman (1990) published a paper on an 
"undescribed Canastero Asthenes species from Brazil". Pearman (1990) 
apparently published his paper, which seems to deal with the same taxon 
as Vielliard's (1990) new species, because: "After carrying out extensive 
fieldwork personally in 1988 and 1989, and due to the long time lapse 
since the original discovery [in 1985], lack of any information on the 
species in the literature and no definite forthcoming description, I feel 
there is a need to publish the present findings" (Pearman 1990: 146). 
Pearman's (1 990) description of the new Asthenes species is based entirely 
on field observations, since "the collecting of specimens was not 
possible". Pearman (1990), like Vielliard (1990) gave no information 
concerning the reasons why the 'new bird' belongs in the genus Asthenes. 
Vocalizations (sonagrams) of the 'new species' are compared to those of 

P. I 'uilleumier, M. LeCroy & E. Mayr 290 Bull. B.O.C. 1 12A 

several species of Asthenes. Clearly, the description of a putative new 
Asthenes in Minas Gerais, many km away from the Andean-Chacoan- 
Patagonian region, where Asthenes is distributed, requires substantiation. 
If correct, such a discovery would be quite interesting biogeographically, 
and would parallel somewhat the case of Schizoeaca, another Furnariidae. 
For the present, however, this is conjectural. There is simply not enough 
evidence and the new name must remain, for the time being, a species 
inquirenda (Ba). The practice of naming putative new species the way 
Asthenes luizae was described is not very professional. 

(30) Philydor novaesi Teixeira & Gonzaga 1983a, Bol. Mus. Paraense 
Emilio Goeldi, Nova Serie Zoologia, No. 124: 4 — 'Serra Branca', 
Municipio de Murici (c. 9°1 5'S, 35°50'W), Alagoas, Brazil, c. 550 m. 
= ? Philydor novaesi (Ba). 

Both the holotype (adult male, number 32029) and the paratype (adult 
male, number 32028) are housed in the Museu Nacional in Rio de 
Janeiro (MNRJ). They were collected almost simultaneously in mist 
nets as part of a mixed flock in a tract of rainforest of northeastern 
Brazil visited during an expedition in February 1979. These specimens 
were compared with series of Philydor atricapillus, the type of Philydor 
hyperythrus, and colour photos of P. hylobius (but about the status of 
P. hylobius see Appendix IV). A black and white drawing (Teixeira & 
Gonzaga 1983a: 8) illustrated the head pattern of the 4 taxa of Philydor. 
P. novaesi differs from P. atricapillus in having a narrower and less 
conspicuous superciliary stripe, and a less well marked postocular 
band. The mystacal stripe of P. novaesi is also less well marked than 
the one in P. atricapillus. The rufous nape band, conspicuous in 
P. atricapillus is lacking in P. novaesi. P. novaesi is larger and heavier 
than P. atricapillus. 

Philydor novaesi and P. atricapillus are allopatric (map in Teixeira & 
Gonzaga 1983a: 13). The authors suggested that the differences between 
P. novaesi and P. atricapillus are sufficient to justify their classification as 
members of a superspecies. 

Since the original description, Teixeria et al. (1987) have reported 4 
additional specimens, including 3 females. "According to this material, 
the females of P. novaesi are identical to males in plumage, and also show 
no trace of the bright nuchal collar which is very conspicuous in the 
closely related Black-capped Foliage gleaner Philydor atricapillus" 
(Teixeira et al. 1987: 155). 

Sibley & Monroe (1990: 408) placed these 2 taxa in the Philydor 
I atricapillus J superspecies. Ridgely (in litt.) believed P. novaesi to be 
a good species; Sick (in litt.) thought that P. novaesi was either an 
"allospecies or geographic race of P. atricapillus"; Fitzpatrick (in litt.), 
however, queried the validity of P. novaesi. 

In view of the fact that 'Philydor hylobius' was recently shown by 
Dickerman et al. (1986) to be a synonym of Automolus roraimae, we 
believe that the identification of the correct status of P. novaesi must await 
further, broader comparisons, including other genera of Furnariidae. We 
classify it for the time being as a species inquirenda (Ba). 

Bull. B.O.C. 1 12A 291 New species 1981-90 


(31) Clytoctantes atrogularis Lanyon, Stotz, & Willard 1990, Wilson 
Bulletin 102(4): 571 — Cachoeira Nazare, west bank of Rio Jiparana, 
Rondonia, Brazil, 9°44'S, 61°53'W, altitude 100 m. 

== Clytoctantes [alixii] atrogularis (Ac). 

The unique type, a female, was mist-netted during an expedition to 
Rondonia. It is housed at the MZUSP (number 66111); colour slides 
are on file at the Field Museum of Natural History (FMNH), Chicago, 
and with VIREO at the Academy of Natural Sciences in Philadelphia. 
Although 2 males were observed, "subsequent attempts to collect more 
specimens and observe it further were unsuccessful" (Lanyon et al. 1990: 
571). The authors point out that they "are reluctant to describe a new 
taxon on the basis of a single specimen", but that "the bird's features are 
so distinctive . . . that [they] believe it represents an undescribed species" 
(Lanyon et al. 1990: 571). A colour plate accompanied the original 

"Within the Formicariidae, only Clytoctantes and Neoctantes share the 
unusual bill shape of the new taxon, in which the upper mandibular tomia 
curve dorsally" (Lanyon et al. 1990: 573). C. atrogularis differs from 
females of C. alixii chiefly in having a black bib, which is lacking in 
C. alixii. An all black-plumaged male appeared, in the field, different 
from the grey and black-bibbed male of C. alixii. l^onyonetal. (1990: 578) 
remarked: "Five experienced observers spent 1400 field hours at the type 
locality and accumulated 1450 net-days. The single netted individual and 
2 sight records suggest that either: (1) this species is extremely uncom- 
mon or secretive, or (2) we encountered only dispersing individuals and 
that it normally occurs in a different habitat." Actually, both possibilities 
are likely; many tropical lowland forest avian species in Amazonia are 
rare. On the basis of the unique type and 2 field sightings, Lanyon et al. 
(1990) concluded that C. atrogularis is, indeed, a valid species and not 
an aberrant C. alixii. It seems likely to us that C. atrogularis is a valid 
new species level taxon, forming a superspecies with distantly allopatric 
C. alixii (Ac), but much more evidence is needed. 

(32) Herpsilochmus parkeri Davis & O'Neill 1986, Wilson Bulletin 98(3): 
338 — c. 1 5 km by trail northeast of Jirillo on the trail to Balsapuerto, 
06°03'S, 76°44'W, altitude 1350m, Department of San Martin, 

= Herpsilochmus pileatus parkeri (Bb). 

The holotype is an adult male deposited in the Louisiana State Univer- 
sity Museum of Zoology (LSUMZ) (No. 1 1 6908). A total of 6 males and 4 
females of this new species are all at LSUMZ. So far, H. parkeri is known 
only from the type locality, an ecologically heterogeneous area consisting 
of a savanna-like habitat, a low-diversity ridge-top habitat on sandy soil, a 
semi-stunted forest, and a tall cloud forest on good soil. il H. parkeri was 
noted most commonly in the canopy and midlevels of the tallest forest" 
(Davis & O'Neill 1986: 343). It also occurred in other habitats, but 
less commonly. H. parkeri was often found in mixed flocks with other 
Formicariidae, Furnariidae and Tyrannidae. 

F. I -uilleumier, M. LeCroy & E. Mayr 292 Bull. B.O.C. 1 12A 

Davis & O'Neill (1986) argued that several taxa of Herpsilochmus, 
hitherto considered to be subspecies of H. pileatus, ought to be treated 
as distinct, allopatric species. H. parkeri is geographically closest to 
motacilloides. The various allopatric taxa of this group of species within 
Herpsilochmus vary slightly in both morphological and vocal characters, 
but not enough data exist as yet about vocalizations. Davis & O'Neill 
(1986: 350-351) considered the question of subspecific vs. specific iden- 
tity of the allopatric trio H. parkeri, H. motacilloides and H. atricapillus y 
and believed that species status is the better alternative at present. 
Furthermore, they "hesitate to classify them [these 3 species plus 
H. pileatus] formally in a single superspecies until the ranges of H. pileatus 
and//, atricapillus are better known" (Davis & O'Neill 1986: 351). Sibley 
& Monroe (1990: 386) included parkeri, motacilloides, atricapillus and 
pileatus in a single superspecies. 

It seems to us that it is not possible to decide on species status at 
present. H. parkeri may be treated as a subspecies of pileatus or as a 
member of the [pileatus] superspecies; for the time being we favour the 
former (Bb). 

(33) Terenura sicki Teixeira & Gonzaga 1983b, Bull. Brit. Orn. CI. 103: 
133 — "Serra Branca", Murici, Alagoas, northeastern Brazil (c. 
9°15'S, 35°50'W). 
= Terenura sicki (Ab). 

This new antbird was originally described on the basis of a single 
female collected in 1979 and deposited in the MNRJ, number 32048 
(Texeira & Gonzaga 1 983b). Further work has permitted the collection of 
5 additional specimens in 1983 (3 males and 2 females, all in the MNRJ), 
and one sub-adult and one adult male (both also in MNRJ) in 1987 
(Teixeira et al. 1988). The holotype is now identified by Teixeira (1987b) 
as an immature female. 

The new taxon is known on the basis of specimens from the type 
locality (Serra Branca, Murici, Alagoas) and from Quebrangulo, Alagoas, 
and from sight records from Novo Lino, Alagoas. The only illustration of 
the new species is a black and white figure of 3 specimens in Teixeira 
(1987b: 244). Details about plumages, habitat, relative abundance, 
behaviour, vocalization and breeding are given in Teixeira (1987b). 
The male resembles in plumage colour and pattern several species of 
Myrmotherula. The female is said to differ from other species of Terenura 
by its orange underparts. Nowhere is it clearly indicated why the new 
taxon was placed in Terenura. 

Remsen {in litt.), Fitzpatrick (in litt.), Sick (in litt.) and Ridgely (in litt.) 
all thought that T. sicki is a valid new species. Sick and Ridgely (in litt.) 
stated that it is close to T. maculata, forming a superspecies with it. 
Sibley & Monroe (1990: 388) accepted T. sicki as a full species (not in a 
superspecies with T. maculata). 

It seems to us that a comparative study of the type series of T. sicki 
with a number of other small Formicariidae should be undertaken before 
the generic status of this form can be fully confirmed. Pending further 
reviews, we accept T. sicki tentatively as a new species (Ab). 

Bull. B.O.C. 1 12A 293 New species 1981-90 

(34) Cercomacra manu Fitzpatrick & Willard 1990, Auk 107(2): 239—12 
river km downstream from Shintuya on left bank of Alto Rio Madre 
de Dios, Dept. Madre de Dios, Peru, 12°33'S, 71°17'W, altitude 
420 m. 

= Cercomacra [melanaria] manu (Ac); or Cercomacra [nigricans] manu 

( Ac >- 

A total of 14 males and 10 females of this new antbird was examined 
(deposited in the LSUMZ, FMNH and AMNH). The holotype, an adult 
female, is number 310653 in the FMNH. C. manu is a member of the 
'Cercomacra nigricans' species group, including 4 allopatric species-level 
taxa besides manu: nigricans, carbonaria, ferdinandi and melanaria. 
C. manu occurs in bamboo habitats (illustrated by photographs) in Peru 
(Depts. Cuzco, Ucayali and Madre de Dios) and Bolivia (Dept. Pando). 
The males of the taxa of the 'nigricans' group are very similar to one 
another, but the females are more distinct (a colour plate accompanied the 
original description). On the basis of several "shared characteristics 
we hypothesize that manu and melanaria are sister taxa, possibly close 
enough to be recognized as a superspecies" (Fitzpatrick & Willard 1990: 
243). C. manu and C. melanaria are allopatric, but their geographical 
disjunction is not nearly as large as that among the other members of 
the 'nigricans' group. We would include manu as an allospecies of either 
the C. [melanaria] superspecies (if only C. manu and C. melanaria 
are included as members), or of the C. [nigricans] superspecies (if all 
allopatric members of this 'group' are included); hence Ac in the 

(35) Grallaria carrikeri Schulenberg & Williams 1982, Wilson Bulletin 
94(2): 105— Cordillera Colan, SE La Peca, c. 5°34'S, 78°19'W, 
altitude 2450 m, Dept. Amazonas, Peru. 
= Grallaria [nuchalis] carrikeri (Ac). 

The type series of this new species consists of 13 specimens, one in 
the Delaware Museum of Natural History and all the others in the 
LSUMZ. The holotype is an adult male (number 88044 at LSUMZ). 
A colour illustration accompanies the original description. G. carrikeri 
is known from 3 localities in the northern Peruvian Andes: Cordillera 
Colan (Dept. Amazonas), near Ingenio on the road to Laguna 
Pomacochas (Dept. Amazonas), and Cumpang, near Ongon (Dept. La 
Libertad). G. carrikeri is closely related to the allopatric G. nuchalis. 
The 2 forms are separated by the low and dry valley of the Rio 
Maranon. The morphological differences (especially whitish bill) and 
vocal differences (including data from some playback experiments) 
suggested to Schulenberg & Williams (1982: 111) that il G. carrikeri has 
achieved species status". Wiedenfeld (1982) has described the nest of 
G. carrikeri and discussed the nests of antpittas. Fitzpatrick {in litt.) y 
Graves (in litt.), Remsen (in litt.) and Ridgely (in litt.) all believe that 
G. carrikeri is a valid species belonging in a superspecies with nuchalis. 
Sibley & Monroe (1990: 417) also placed nuchalis and carrikeri in the 
G. [nuchalis] superspecies. We accept this view here and classify 
carrikeri as Ac. 

F. I 'uilleumier, M. LeCroy & E. Mayr 294 Bull. B.O.C. 1 12A 

(36) Grallaria blakei Graves 1987, Wilson Bulletin 99(3): 314 — east slope 
of the Cordillera Carpish, near the Carretera Central, c. 2400 m. 
altitude, Department of Huanuco, Peru. 

= Grallaria blakei (Ab). 

This new species, described on the basis of 8 specimens (one in the 
FMNH and 7 in the LSUMZ) occurs at 3 localities along the eastern 
Peruvian Andes in the Departments of Huanuco and Amazonas, between 
2135 and 2470 m. At Cordillera Carpish and Cordillera Colan, where 

G. blakei has been collected nearly sympatrically with the very similar and 
widespread G. rufula, "a distributional hiatus is found between their 
known elevational ranges" (Graves 1987: 320). Graves (1987: 320) added 
that "whether this gap is real or an artefact of sampling is not known". 
The holotype (adult female) is number 64228 in the LSUMZ. A colour 
plate of G. blakei accompanied the original description. G. blakei differs 
slightly from G. rufula in colour and size. 

Sibley & Monroe (1990: 418) listed G. blakei as a full species. How- 
ever, as Graves (1987) himself pointed out, more evidence is needed on 
the status of these 2 forms in their contact areas. For the time being, 
we classify G. blakei as Ab, but look forward to more corroborating 

(37) Grallaricula ochraceifrons Graves, O'Neill & Parker 1983, Wilson 
Bulletin 95(1): 1— 10 km (by road) below (NE) Abra Patricia, 
altitude c. 1890 m (6200 ft), 5°46'S, 77°41'W, Depto. San Martin, 

= Grallaricula [peruviana] ochraceifrons (Ac). 

The holotype (LSUMZ number 81998) is an adult male. The type 
series consists of 5 specimens (all at LSUMZ) collected at 2 localities in 
northern Peru (Depts of San Martin and Amazonas), at altitudes from 
1890 to 1980 m. A colour plate and a black and white photograph of a 
live, hand held bird, accompany the original description. G. ochraceifrons 
is sexually dimorphic (although only 1 $ has been collected to date). 
G. peruviana, which is allopatric with G. ochraceifrons and separated from 
it by the dry Maranon Valley, is also sexually dimorphic. Unfortunately 
the vocalizations of G. ochraceifrons are unknown. Tentatively, Graves et 
al. (1983: 4) suggested that G. peruviana and G. ochraceifrons are mem- 
bers of the same superspecies. Graves (in litt.) wrote that G. ochraceifrons 
was "perhaps superspecifically related to either G. lineifrons or 
G. peruviana". Fitzpatrick (in litt.) thought G. ochraceifrons to belong in 
a superspecies with G. peruviana. Sibley & Monroe (1990: 419) placed 
peruviana and ochraceifrons in the G. [peruviana] superspecies. We treat 
it here as Ac, but more evidence (specimens, vocalizations) is clearly 


(38) Scytalopus psychopompus Teixeira & Carnevalli, 1989, Bol. Mus. 

Nac, Nov. Ser., Zool., no. 331: 2 — Valenca, Bahia, Brazil. 
= Scytalopus / indigoticus] psychopompus (Ac). 

Bull. B.O.C. 1 12A 295 New species 1981-90 

Based on 3 specimens, 2 housed in the MNRJ and one in the Museu 
de Zoologia of the University of Sao Paulo (one adult female holotype, 
MN number 34371, and 2 males), this new species has been collected at 
Valenca, Bahia and Ilheus, Bahia, in northeastern Brazil. S . psychopompus 
is allopatric with the widespread S. indigoticus . A photograph in the 
original description shows the 2 species (female specimens) side by side. 
S. psychopompus differs from S. indigoticus in having uniform (unbarred) 
chestnut on the flanks and crissum. S. psychopompus was compared with 
a large series of S. indigoticus, which shows a substantial amount of 
individual variation, but which always seems to have barring on the 
crissum or flanks. Tentatively we list S. psychopompus as an allospecies 
of S. [indigoticus] (Ac). Much more information on individual variation 
and especially new data on voice are needed for the Bahia populations. 
Scytalopus is a notoriously difficult genus. 


(39) Phylloscartes ceciliae Teixeira 1987a, Bull. Brit. Orn. CI. 107(1): 
38 — 'Serra Branca', Murici, Alagoas, northeastern Brazil (c. 9°15'S, 
35°50 , W), altitude 550 m. 

= ? Phylloscartes ceciliae (Ba). 

Described on the basis of 5 specimens collected in 1983 and 1984 
(Teixeira 1987a), to which were added 4 specimens collected in 1987 
(Teixeira et al. 1988), this new species occurs in Alagoas (2 localities). All 
specimens are in the MNRJ. The holotype, an adult male, is number 
34041 . It is not clear to what other species of Phylloscartes (sensu stricto or 
sensu lato?) the putative new species has been compared, since the original 
description does not indicate what comparative material (if any) was used. 
A black and white line drawing in the original description is the only 
illustration of P. ceciliae. Sibley & Monroe (1990: 347) accepted P. ceciliae 
as a valid species. 

Given the difficulties of Tyrannidae systematics, and the very incom- 
plete nature of the description, however, we feel that we do not have 
enough information about P. ceciliae at present for us to classify it as 
anything but a species inquirenda (Ba). 

(40) Phylloscartes lanyoni Graves 1988, Wilson Bulletin 100(4): 529— El 
Pescado, 12 km below Pto. Valdivia on the Rio Cauca, c. 1500- 
1700 ft [457-518 m], Department of Antioquia, Colombia. 

= ? Phylloscartes lanyoni (Ba). 

Known only from the holotype, an adult male at the USNM, 
Washington, DC (number 402716), the type locality of this new 
Phylloscartes is distant from the ranges of P. venezuelanus and P. orbitalis 
(colour plate in original description). As Graves (1988: 532) himself 
stated: "Based on the similarity of body plumage and reduced auricular 
spot, P. lanyoni appears to be a trans-Andean relative of P. orbitalis, 
although a close relationship to P. venezuelanus and P. gualaguizae is 
possible." Given this uncertainty, Sibley & Monroe's (1990: 346) 
inclusion of this species in a superspecies with P. orbitalis appears 

F. I 'uilleumier, M. LeCroy & E. Mayr 296 Bull. B.O.C. 1 1 2A 

Further research on song and other characteristics is needed to deter- 
mine the rank of these forms. Owing to the great similarity of species in 
this genus it is difficult to decide whether allopatric populations should be 
ranked as subspecies or allospecies. We classify it conservatively here as a 
species inquirenda (Ba). 


(41) Thryothorus eisenmanni Parker & O'Neill, 1985, American Orn. 
Union, Orn. Monogr. no. 36: 9 — San Luis on Ollantaitambo- 
Quillabamba road, above Huyro, 13°06'S, 72°25'W, altitude '9000 
feet' [2744 m], Department of Cuzco, Peru. 

= Thryothorus euophrys eisenmanni (Bb). 

Based on 16 specimens, all at the LSUMZ except one (at the AMNH), 
this new wren is closely related to T. euophrys. T. eisenmanni occurs from 
1 830 to 3350 m in montane forest with dense bamboo thickets, apparently 
its favoured habitat, in the Department of Cuzco (eastern Peruvian 
Andes). The holotype is an adult male (LSUMZ number 78913). A 
colour plate accompanied the original description. 

Some playback experiments showed that T. euophrys atriceps individ- 
uals respond much more strongly to songs of T. euophrys longipes than to 
songs of T. eisenmanni, "which supports our taxonomic decision to regard 
eisenmanni as a full species" (Parker & O'Neill 1985: 12). Ridgely (in 
litt.) suggested that T. eisenmanni is "close to euophrys". Graves (in 
lift.) and Fitzpatrick (in litt.) would put T. eisenmanni as "allospecies 
of T. euophrys". Sibley & Monroe (1990: 560) treated euophrys and 
eisenmanni as members of the T. [euophrys] superspecies. We believe, 
however, that eisenmanni is a well-marked subspecies of euophrys, and 
treat it tentatively as Bb here. 

Emberizidae (Thraupinae) 

(42) Tangara meyerdeschauenseei Schulenberg & Binford 1985, Wilson 
Bulletin 97(4): 413 — 2 km northeast of Sandia, c. 2175 m altitude, 
14°17'S, 69°26'W, Department of Puno, Peru. 

= Tangara [cay ana] meyerdeschauenseei (Ac). 

Based on 4 specimens in the LSUMZ (2) and the MNHN, (2), this new 
Tangara occurs in the Andes of southeastern Peru (Dept. Puno). The 
holotype is an adult male, number 98917 in LSUMZ. A colour plate 
accompanied the original description. This montane Tangara is clearly 
a member of the group of species of the "cay ana group", including 
taxa flava, cucullata and vitriolina. T. meyerdeschauenseei differs from 
these other taxa in several characters, including the lack of orange or 
rufous-buff crown. 

Sibley & Monroe (1990: 755) accepted meyerdeschauenseei as a valid 
species but did not include it in any superspecies. Other workers, how- 
ever, feel that this species is closely allied to other allopatric species. 
Graves (in litt.) thought that T. meyerdeschauenseei was "probably an 
allospecies of T. vitriolina". Fitzpatrick (in litt.) thought that it belonged 
in the same superspecies as cayana and vitriolina. Ridgely (in litt.) also felt 

Bull. B.O.C. 1 12A 297 New species 1981-90 

that it belonged "clearly in the cay ana complex". We list it here as a 
member of the T. [cay ana J superspecies (Ac). 

(43) Tangara phillipsi Graves & Weske 1987, Wilson Bulletin 99(1 ):1 — 
Cerros del Sira, 9°26'S, 74°45'W, 1 300 m altitude, Departamento de 
Huanuco, Peru. 
= Tangara heinei phillipsi (Bb). 

The holotype is deposited at the AMNH (No. 820969). One other 
specimen is at the AMNH, and 2 more at the Zoological Museum of the 
University of Hamburg, Germany. The new species is darker than, but 
otherwise is quite similar to, allopatric T. heinei. Graves & Weske (1987: 
4) placed heinei and phillipsi in the same superspecies, and Sibley & 
Monroe (1990: 756) adopted this procedure. We feel that phillipsi is not 
very different from heinei and therefore might be considered a subspecies 
of T. heinei. We so consider it here (Bb). 


Of the 43 species described as new in 1981—1990, 24 (58%) can be con- 
sidered good species. Of these 24 species, 13 (54%) belong to super- 
species. An average of 2.4 good new species per year were thus described 
in 1981-1990. This rate is identicial to the figure for the 5-year period 
1976-1980. Earlier average figures are 3.1 /year for 1966-1975, 3. 5 /year 
for 1956-1965, 2.6/year for 1941-1955, and 6.0/year for 1938-1941. 
162 good new species of birds have been described in the 52 years from 
1938-1 990, a rate of about 3 . 1 /year. 

In 1981-1990, one new species has been reduced to the synonym of an 
already known species. We consider 8 of the new species as probably 
subspecies of already known species. Finally, 10 species are kept here 
tentatively as species inquirenda pending further research into their status. 

Even though our summary above seems to indicate that the new species 
can easily be assigned to a given category, in practice many uncertainties 
still exist. In particular many new species belong to allopatric groups of 
taxa which on present evidence could be considered either as allospecies 
or subspecies. In the text we have taken some pains to point out these 
difficulties, thereby hoping to spur further needed new research on these 
forms. We would like to stress here the importance of having more speci- 
mens and more complete data in hand before descriptions are attempted. 
We present specific guidelines for species descriptions in a separate paper 
in this volume. 


A total of 43 species of birds was described as new in the 10 year period 
from 1981-1990. Of these, 24 can be considered 'good' species: 

Aa New species in new genera: None. 

Ab New species not clearly members of a superspecies (1 1): 5, 7, 9, 11, 

Ac Allospecies (members of a superspecies) (13): 2, 10, 12, 17, 20, 23, 24, 


F. I 'uilUtamer, M. Lei 'toy & E. Mayr 298 

Bull.B.O.C. 112A 

An additional 19 names cannot now be assigned the status of valid full 

Ba Species inquirendae (10) 3, 4, 6, 8, 19, 25, 29, 30, 39, 40. 

Bb Subspecies (8): 1, 13, 15, 27, 28, 32, 41, 43. 

Be Synonyms (1): 14. 

Bd Invalid names: none. 


We acknowledge our debt to the following colleagues, who generously made critical com- 
ments and helped us greatly during the preparation of this review: Dean Amadon, Allison V. 
Andors, John Ash, Richard C. Banks, Bruce Beehler, Robert Bleiweiss, Walter Bock, 
Walter E. Boles, W. Ralph Browning, John Cox, Jared Diamond, Jean Dorst, Christian 
Erard, John Fitzpatrick, Gary Graves, Philip Humphrey, Ned Johnson, C. Jouanin, Allen 
Keast, Stuart Keith, Ben King, Scott Lanyon, Manuel Nores, Storrs Olson, Shane Parker, 
Kenneth Parkes, Robert Ridgely, Richard Schodde, Lester Short, the late Helmut Sick, 
David Snow, Melvin Traylor, Jr., Van Remsen and Richard Zusi. We are grateful to Helen 
Kwon and Elizabeth De Jesus who typed the manuscript, and to James Monk for his careful 
editing of the manuscript. 


Alphabetical list of the 43 putative new species described from 

1981 to 1990 
(Numbers in parenthesis refer to the species' number in the 


Amazona kawalli (25) 
Asthenes luizae (29) 
Batis occultus (15) 
Calidris paramelanotos (3) 
Caprimulgus prigoginei (5) 
Cercomacra manu (34) 
Cettia carolinae (11) 
Cichlornis llaneae (12) 
Clytoctantes atrogularis (31) 
Diomedea amsterdamensis (1) 
Gerygone ruficauda ( 1 4) 
Glaucidium albertinum (4) 
Grallaria blakei (36) 
Grallaria carrikeri (35) 
Grallaricula ochraceifrons (37) 
Herpsilochmus parkeri (32) 
H ir undo per dita (8) 
Malurus campbelli (13) 
Melignomon eisentrauti (6) 
Meliphaga hindwoodi (17) 
Mirafra ashi (7) 
Nectarinia rufipennis ( 1 6) 

Otus hoyi (27) 
Otus marshalli (26) 
Otus peter soni (28) 
Philydor novaesi (30) 
Phyllastrephus leucolepis (9) 
Phylloscartes ceciliae (39) 
Phylloscartes lanyoni (40) 
Ploceus burnieri (18) 
Ploceus ruweti (20) 
Ploceus victoriae (19) 
Pyrrhura orcesi (24) 
Rallus okinawae (2) 
Scytalopus psychopompus (38) 
Stachyris latistriata (10) 
Tachyeres leucocephalus (23) 
Tangara meyerdeschauenseei (42) 
Tangara phillipsi (43) 
Terenura sicki (33) 
Thryothorus eisenmanni (41 ) 
Vidua larvaticola (22) 
Vidua raricola (21 ) 

Bull. B.O.C. 1 12A 299 New species 1981-90 





Lophura hatinhensis Vo Quy 1975, Birds of Vietnam: 245. 
= ? Lophura hatinhensis (Ba). 

The single existing specimen of this new taxon (a male, no number or 
place of deposition are given in the description) was compared to closely 
related pheasants "like L. imperialis Delacour and Jabouille, L. edwardsi 
Oustalet in Viet Nam, L. inornata Salvadori in Sumatra and L. swinhoei 
Gould in Taiwan". The new species is "closest to L. edwardsi the only 
difference is [L. edwardsi] has darker color, there is no shiny green [in the 
upper wing coverts] and there are no middle four white tail feathers". 
Measurements: "wing 245; tail 270; feet 89; beak 30 mm. Weight 

We overlooked this species in the account for the period 1966-1975 
(Mayr & Vuilleumier 1983), as pointed out to us by King (pers. comm.). 
It has been extremely difficult for us to obtain copies of the original 
description. We are grateful to Craig Robson for sending us a copy of this 
description and to Toan Nguyen for translating it. 

Recent accounts in the western literature include that of Collar & 
Andrew (1988: 38), who stated that this species is "only known from a 
small area south of Vinh in several adjacent valleys on the eastern slopes 
of the mountains, preferring lower altitudes than Edwards' Pheasant 
L. edwardsi'. Robson et al. (1989: 76) stated that Lophura hatinhensis "is 
only known to occur in the vicinity of the type-locality: Song Tund, and 
adjacent Ky Thuong sub-district". They added: "The original and only 
(existing) specimen was collected in 1964 by the late Do Ngoc Quang. A 
second specimen was collected from Ky Thuong sub-district in 1974 by 
T. V. L. [Truong Van La], but was not preserved in its entirety." A 
popular account has been published in German (see Bahr & Nguyen 
1992) including a photograph in colour of a living bird in the Hanoi zoo. 

In the absence of further information, we feel we cannot comment on 
whether Lophura hatinhensis is a recognizable species. As an allopatric 
population closely related to L. edwardsi ', L. hatinhensis might be con- 
sidered either as a subspecies or an allospecies. Until further information 
is available, upon which to base a decision, we prefer to classify it as Ba. 


Nyctisyrigmus kwalensis, Davis 1978, Pan American Studies 1(2): 47 — 

Kwale, SE Kenya. 
= ? Caprimulgus pectoralis (Bd). 

This new species and the next (Allasma northi) were omitted from the 
1976-1980 account (Vuilleumier & Mayr 1987), and we thank Ralph 
Browning for bringing them to our attention. 

/•'. I uillcumter, M. LeCroy & E. Mayr 300 Bull. B.O.C. 1 1 2A 

Nyctisyrigmus kwalensis was described on the basis of tape recordings of 
songs. We quote from Davis (1978: 47): "Diagnosis: External morpho- 
logical characters are the same as those of other members of the 
Caprimulginae (sic). The species specific song is a typical two figure 
phrase of the genus Nyctisyrigmus in which the terminal portion of the 
second figure shows frequency modulation." And further: "The type 
song phrase specimen is listed under 'species with whistling songs' and is 
number '4' of the 'Dusky or South African Nightjar — Caprimulgus 
pectoralis' group in the Myles North papers. North gave credit for the 
recording to Keith and said it was from Kwale, SE Kenya and made in 

This name is thus based exclusively on a sonagram. It is a nomen nudum, 
a conclusion that agrees with that reached by Browning & Richard Banks 
(in litt.). 

Allasma northi, Davis 1978, Pan American Studies, 1(2): 52 — no type 

locality given. 
= ? Caprimulgus clarus (Bd). 

"The type song phrase specimen is listed as number '4' in the group 
of recordings discussed under: 'SLENDER-TAILED NIGHTJAR'— 
Caprimulgus clarus Reichnow (sic). This heading comes on page 5 of the 
by Myles E. W. North. The paper is rather widely circulated and is found 
in various Museums" (Davis 1978: 52). 

Described solely on the basis of sonagrams, as was the previous species, 
this new name is a nomen nudum without nomenclatural validity. We agree 
in this with Browning & Banks (in litt.). 



We list below 2 taxa that have been mentioned in the literature as new 
or potentially new, but that the authors have refrained from naming as 
new species. Note that this listing does not pretend to be complete, as 
we cite only those papers that have come to our attention during our 
search for new species' descriptions. We include these accounts here 
only to warn ornithologists who might be tempted to designate such 
populations as new species in the future, that they must do so in pro- 
fessional fashion, with a precise description and designation of type 


Muscicapidae (Sylviinae) 

Phylloscopus sp. 

Alstrom et al. (1990) heard and saw Phylloscopus warblers in Sichuan 
Province and Hebei Province, China, in 1986, 1988 and 1989, that were 

Bull. B.O.C. 1 12A 301 New species 1981-90 

distinct from P. (p.) chloronotus (for taxonomy of P. proregulus and P. (p.) 
chloronotus see Alstrom & Olsson 1990). No specimens were obtained. 
On the basis of visual and voice observations, the differences between 
"Phylloscopus sp." and P. chloronotus were listed. Playback tests of P. (p.) 
chloronotus vocalizations showed "no response whatsoever to the P. sp. 
song and 'calls', but a very strong aggressive response to its own song" 
(Alstrom et al. 1990: 45-46). 

We wish to compliment the authors for their restraint. Despite exten- 
sive field experience with the 'new' taxon, they declined formally to name 
it until specimens are collected. 



Patagona sp. 

Fjeldsa & Barbosa (1983) suggested that a new species of Patagona 
occurs in the Andes of NE Colombia, based on the observations of a 
single bird in October 1981. Such an occurrence would be of interest, 
since Patagona currently has a single species, gigas, and since this 
would represent a northward extension of 900 km as well as an eco- 
logical shift. After careful study of the Fjeldsa & Barbosa (1983) 
paper, Robert Bleiweiss and one of us (F.V., unpub. ms.) believe that 
there is not enough evidence to warrant the suggestion of a new 
species of Patagona. No specimen of the purported new taxon was 
collected, and the informal description of the putative new form is 
not a diagnosis and does not even permit unquestionable generic 
assignment. In fact, the information provided by Fjeldsa & Barbosa 
(1983) is equally consistent with the identification of the observed 
bird as a female Pterophanes in slightly unusual plumage. Pterophanes 
is the second largest hummingbird, close to Patagona in size, and is 
known to occur in the region where the purported Patagona was 

Only a few characters of the described bird indicate that it could be a 
Patagona. These include light undertail coverts, and a non-uniform tail 
colour, darkest distally. No mention is made, however, of the rump, 
which is uniquely white in all known Patagona populations and could 
thus serve as a diagnostic feature. Other characters are equally consistent 
with either Patagona or Pterophanes: long forked tail, and slow wingbeat. 
The majority of characters suggest Pterophanes. Fjeldsa & Barbosa (1983) 
claim that female Pterophanes have extensive green discs on rufous under- 
pays, but female Pterophanes in the collection of the AMNH have 
uniform rufous underparts, as in the bird they described. The dark back 
with a green lustre, and a straight bill, thinner than that of Patagona, are 
also both characteristic of Pterophanes. 

Plumage variants and morphs are not uncommon in the Trochilidae. 
This possibility should be considered before any attempt at a formal 
taxonomic description of this bird is made. Until such time as specimens 
are collected, Bleiweiss and Vuilleumier advise that the suggestion of a 
new species of Patagona be disregarded. 

F I uilleumier, M. LeCroy & E. Mayr 302 Bull. B.O.C. 1 12A 



We comment below on 13 species described in earlier accounts (Mayr 
1971 , Mayr & Vuilleumier 1983, Vuilleumier & Mayr 1987) and for which 
new information has appeared in the literature since our earlier reviews. 



Zoothera kibalensis = 1 Zoothera kibalensis 

In the instalment for the years 1976-1980 Vuilleumier & Mayr (1983: 
1 38) treated Z. kibalensis (Prigogine 1978) "as a species inquirenda pending 
either further specimens or life history information". In a later paper, 
Prigogine ( 1 989: 1 89) reported that a recent search for this bird had failed, 
but that "it is possible that this ground-thrush will be recorded finally 
when the search will be extended in a convenient biotype, at an altitude 
near 1,500 metres". Prigogine stated that the 2 specimens of kibalensis 
"have nothing in common with . . . Zoothera princei" > that kibalensis is 
heavier than Z. camaronensis graueri, and that the characters of the 2 
specimens of kibalensis are such as to rule out hybridization between 
earner onensis and princei. He concluded: "For these reasons Z. kibalensis 
must be retained as a good species" (Prigogine 1989). 

Keith (pers. comm.), who is editing Zoothera for Vol. 5 of The Birds of 
Africa, does not intend to treat it as a valid species unless further evidence 
is forthcoming on voice and behaviour. R. J. Dowsett (pers. comm. to 
Keith) does not believe Z. kibalensis to be a good species, and it does not 
appear in his forthcoming Checklist of Afrotropical Birds. We prefer to 
retain it as a species inquirenda for the time being, as did Sibley & Monroe 


Sitta ledanti = S. [krueperi] ledanti 

Bellatreche & Chalabi (1990) and Bellatreche (1991) have reported new 
localities for this new nuthatch (Vielliard 1976), which is not restricted to 
Abies numidica habitats as was previously believed, but also occurs in 3 
other areas between 900 and 1400 m in oak (Quercus canariensis and 
Q. afares) woodlands. The 4 locations are: Djebel Babor (2300 ha.), 
Guerrouch Forest (10,500 ha.), Tamentout Forest (9600 ha.) and Djimla 
Forest (1000 ha.). The population size of this nuthatch is therefore larger 
than once thought, and its habitat requirements more varied. 



Crax estudilloi= ICrax estudilloi 

The saga of Crax estudilloi Allen et al. (1977), reported by Vuilleumier 
& Mayr (1987) in the 1976-1980 instalment, continues. The bird died 

Bull. B.O.C. 1 12A 303 New species 1981-90 

when still not fully adult, and much effort was expended to send the 
specimen frozen to Louisiana State University Museum of Zoology. 
Unfortunately, it arrived in a decomposed state, and it was possible to 
save only the skeleton and a few feathers — LSUMZ No. 140000 (V. 
Remsen, pers. comm.). 

Remsen & Traylor (1989: 56) discussed this bird and concluded: 
"Although a number of cracid experts feel that this bird represents a valid 
species, we remain cautious until a thorough analysis of the specimen is 
completed; therefore, we follow Vuilleumier & Mayr (1987) in listing this 
as a species inquirenda." Sibley & Monroe (1990: 9) regarded it "as a likely 
hybrid between C . fasciolata and some other Crax species". 


In the 1976-1980 instalment Vuilleumier & Mayr (1987) gave additional 
information on 6 putative new species of hummingbirds in the genera 
Threnetes (3 species) and Phaethornis (3 species) that they had reviewed 
previously (Mayr & Vuilleumier 1 983). We provide below some additional 
comments resulting from useful critical studies by Hinkelman (1988a, 

Threnetes cristinae = Threnetes leucurus loehkeni. 

In an earlier paper (Mayr & Vuilleumier 1983) it was suggested that 
T. cristinae Ruschi (1975) was likely to be a "synonym of Threnetes 
( ? leucurus) loehkeni ' . Hinkelmann's ( 1 988b) discussion makes it clear that 
"there remains little doubt that i T. cristinae' is merely a synonym of 
Threnetes leucurus loehkeni'. 

Threnetes loehkeni = Threnetes leucurus loehkeni 

In an earlier account (Mayr & Vuilleumier 1983) it was thought that 
T. loehkeni Grantsau (1969) was a subspecies of leucurus, but later 
Vuilleumier & Mayr (1987) concluded that loehkeni was a recognizable 
species. Grantsau (in Vuilleumier & Mayr 1987) thought that Threnetes 
niger freirei is the adult of "7\ loehkeni". Hinkelmann (1988b) concluded 
that "until more recently collected Threnetes specimens are available 
from Amapa, Brazil, and from French Guiana, the taxonomic affinities 
between T. niger and T. leucurus remain obscure, and the best treatment 
of loehkeni for the present is as a distinctive subspecies of T. leucurus". 
We concur. 

Threnetes grzimeki = Glaucis hirsuta 

That T. grzimeki Ruschi (1973b) is a synonym of Glaucis hirsuta, an 
opinion reached earlier by Vuilleumier & Mayr (1987), is in agreement 
with Hinkelmann (1988b). 

Phaethornis margarettae — Phaethornis malaris margarettae 

P. margarettae Ruschi (1972), based on the 10 specimens available to 
Ruschi and an additional 8 specimens listed by Hinkelmann (1988b), is 
not easy to define. Hinkelmann (1988b), after a review of the evidence, 
concluded that he agrees (with various authors) "in considering 

F. I -uilleumier, M. LeCroy & E. Mayr 304 Bull. B.O.C. 1 12A 

murgarettae a subspecies of the P. super ciliosusj malaris species group but 
prefer[s] to treat it as P. malaris margarettae until further information 
concerning its relationship to P. malaris insignis is available". This seems 
a wise suggestion to us. 

Phaethornis nigrirostris = Phaethornis eurynome eurynome 

The question of the status of P. nigrirostris Ruschi (1973a) seems to 
have been solved by Hinkelmann (1988b): "I consider l P. nigrirostris' 
to represent aberrant black-billed individuals occurring within the 
P. eurynome population in the Nova Lombardia Reserve, Espirito Santo, 
Brazil". " 

Phaethornis maranhaoensis = Phaethornis natter eri 

In 1983 Mayr & Vuilleumier had listed P. maranhaoensis Grantsau 
(1968) as species inquirenda, and in 1987 Vuilleumier & Mayr accepted 
Grantsau's view of specific distinctness. Hinkelmann (1988a) carried out 
a detailed study of maranhaoensis and concluded that "the description of 
Phaethornis maranhaoensis Grantsau 1968 is based on the previously 
undescribed male plumage of Phaethornis nattereri Berlepsch 1887; 
P. maranhaoensis should, therefore, be regarded as synonymous with 
P. nattereri". We agree with Hinkelmann (1988a). 


Cine lodes olrogi= ? Cinclodes fuscus olrogi 

Vuilleumier & Mayr (1987) discussed Cinclodes olrogi Nores & 
Yzurieta (1979) and concluded: "We tentatively list this species as an 
allospecies of oustaleti, but we are aware that a thorough comparative 
study of Cinclodes spp. carried out in the Sierra de Cordoba and in 
the Andes of Argentina might modify this conclusion". Nores (1986) 
described a new subspecies (riojanus) of Cinclodes fuscus from La Rioja, 
and compared this new taxon to several other subspecies of fuscus 
(albiventris, tucumanus, rufus and yzurietae) and to olrogi. Resemblances 
between C. fuscus riojanus and C. olrogi prompted Nores (1986) to con- 
clude that "C. olrogi is not a species, but a subspecies of C. fuscus, a species 
which has differentiated into several subspecies in the montane zone of 
Argentina, especially in the Sierras Pampeanas". Unfortunately, Nores 
( 1 986) did not compare olrogi to C. oustaleti. Although it now seems more 
likely to us that olrogi belongs to C. fuscus than to C. oustaleti, as we had 
believed earlier, we still feel the need for more study. It is retained as an 
allospecies by Sibley & Monroe (1990: 395). 

Philydor hylobius = Automolus roraimae 

Mayr (1971), in the new species instalment for 1956-1965, considered 
Philydor hylobius Wetmore & Phelps (1956) as a valid species, "similar to 
and related to P. atricapillus" , and classified it as Ad (allospecies which 
some authors would consider merely subspecies). Recent collections 
in the Cerro de la Neblina area did not include new material of this 
taxon. Additional material of Automolus roraimae, however, permitted 
Dickerman et al. (1986) to conclude that the juvenile Philydor hylobius in 

Bull. B.O.C. 1 12A 305 New species 1981-90 

the USNM was 'inseparable' from juvenile Automolus roraimae, and that 
the adult Philydor hylobius (the type) "is actually an erythristic specimen 
of A. roraimae" . Thus "Philydor hylobius Wetmore and Phelps should 
be considered a junior synonym of Automolus roraimae Hellmayr" 
(Dickerman et al. 1986: 431). 


Serpophaga griseiceps = Serpophaga subcristata munda 

Serpophaga griseiceps Berlioz (1959), which Mayr (1971) had con- 
sidered as a new species not clearly a member of a superspecies, "very 
similar to munda" , is actually a synonym of S. subcristata munda (Traylor 
1979: 41). Sibley & Monroe (1990: 344) treat munda as a distinct species 
(fide J. V. Remsen) on the basis of differences in vocalizations between it 
and subscristata. 

Todirostrum albifacies = Poecilotriccus tricolor 

T. albifacies Blake (1959), reviewed by Mayr (1971) and considered 
as a full species in the superspecies T. capitate, is in fact a synonym of 
Poecilotriccus tricolor (Traylor 1979: 77). 


Allen, G. A. Jr., Allen, G. A. Ill & Allen, L. 1977. A new species of currasow discovered. 

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warbler of the genus Phylloscopus from China. Bull. Brit. Orn. CI. 110: 43—47. 

— & Olsson, U. 1990. Taxonomy of the Phylloscopus proregulus complex. Bull. Brit. Orn. 

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— 1987. Ploceus victoriae. Ibis 129: 406^107. 

Bahr, N. & Nguyen, C. 1992. Der Vo Quy-Fasan. Ornis 3:12-13. 

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CI. 110:51-58. 
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— & Chalabi, B. 1990. Donnees nouvelles sui l'aire de distribution de la Sitelle [sic] kabyle 

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— 1982. A new species of Mirafra (Alaudidae) and new races of the Somali Long-billed 

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— 1988. Phylloscartes lanyoni, a new species of bristle-tyrant (Tyrannidae) from the lower 

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— & Weske, J. S. 1987. Tangaraphillipsi, a new species of tanager from the Cerros del Sira, 

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Addresses : Francois Vuilleumier and Mary LeCroy, Department of Ornithology, American 
Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, 
USA; Ernst Mayr, Museum of Comparative Zoology, Harvard University, 
Cambridge, Massachusetts 02138, USA. 

© British Ornithologists' Club 1992 

311 Bull.B.O.C. 112A 


One hundred years on, the founding fathers of the British Ornithologists' 
Club would be daunted indeed by today's systematics and its specialised 
techniques. They would, too, be dismayed at the disregard amounting to 
disdain of trustees and managers of the great natural history museums of 
Europe for orthodox museum work and research. They would approve 
greatly of modern sophisticated field identification and methods, and the 
undreamed of optical and sound-recording facilities by which they 
prosper, even maybe to the extent of dismissing their doubts on the 
admissibility of sight records. They would be equally astonished at what 
they would deem the mistaken sentimentality towards collecting speci- 
mens for museum work, to them the heart of taxonomy and systematics - 
as indeed it is to the diminishing band of museum based workers still 
pursuing their calling today. 

Taxonomy being essentially based on skill and experience in making 
comparisons between closely similar or unlike or totally dissimilar speci- 
mens, if species and subspecies are to remain the foundation building 
blocks of systematics, it is hard to see how an unambigously designated 
type specimen - in birds, in the form of the conventional museum 'skin' - 
can be dispensed with. Relationships beween families and genera may 
well in due course become convincingly determined by ever increasingly 
sophisticated methods of assaying hereditary characters; but will the sub- 
jectivity involved in measuring and judging the degree of difference 
between museum specimens become a thing of the past, substituted per- 
haps by drops of blood or by frozen tissue? Plainly that time has not yet 

This volume draws attention to and emphasises the importance of avian 
systematics and taxonomy, so long a leader in advancing theories in the 
wider field of evolution. It is manifestly an active science, not merely in its 
own at present somewhat disparaged field, but also in its academic role and 
the application of its expertise for the better understanding of problems in 
other zoological disciplines. It is to be hoped that fresh thinking by the 
proponents of present day museum management may yet revert to 
encouraging the creative use of the historic collections in their care, which 
originated with the immediate forefathers of the founders of the British 
Ornithologists' Club. 


© British Ornithologists' Club 1992 




bock, w. j. Status and future activities of the Standing Committee 

on Ornithological Nomenclature of the International Ornitho- 
logical Committee (IOC) 3 

amadon, D. & short, L. L. Taxonomy of lower categories — 

suggested guidelines 11 

barrowclough, G. F. Biochemical studies of the higher level 

systematics of birds 39 

bock, w. j. Methodology in avian macrosystematics 53 

clancey, p. a. Subspeciation, clines and contact zones in the 

southern Afrotropical avifauna 73 

fry, c. H. Myrmecophagy by Pseudochelidon eurystomina and other 

African birds 87 

grant, p. R. Systematics and micro-evolution 97 

haffer, j. The history of species concepts and species limits in 

ornithology 107 

JACOB, j. Systematics and the analysis of integumental lipids: the 

uropygial gland 159 

knox, A. G. & Walters, M. Under the skin: the bird collections of 

the Natural History Museum 169 

lecro y, m. & vuilleumier, f. Guidelines for the description of new 

species in ornithology 191 

lohrl, h. & thaler, e. Behavioural traits as an aid to solving 

taxonomic problems 199 

louette, m. Barriers, contact zones and subspeciation in central 

equatorial Africa 209 

morel, G. j. & chappuis, c. Past and future taxonomic research in 

West Africa 217 

ouellet, h. Speciation, zoogeography and taxonomic problems in 

the Neotropical genus Sporophila (Aves: Emberizinae) 225 

panov, e. n. Emergence of hybridogenous polymorphism in the 

Oenanthe picata complex 237 

potapov, r. l. Systematic position and taxonomic level of grouse 

in the order Galliformes 251 

voous, k. h. Reflections on the genus in ornithology 261 

vuilleumier, f., lecroy, m. & mayr, E. New species of birds 

described from 1981 to 1990 267 

monk, j. f. Epilogue 311 

Published by the BRITISH ORNITHOLOGISTS' CLUB and printed by 
Henry Ling Ltd., at the Dorset Press, Dorchester, Dorset